following procedures are general in nature and intended for use by computer
professionals or competent, experienced users. I will not be held
responsible for any problems or damages of any kind resulting from the use or
misuse of the information posted here. More Specific Information can be
found in the USB
[Host Side] [IRQs] [NTKERN.VXD Error]
[Non-Intel USB] [Peripherals]
[Older Systems] [PCI/USB]
Host Side Issues
To achieve proper USB connectivity
system elements must be
present and working correctly.
1) Support from the BIOS
2) Support from the Operating System
3) Physical USB ports
4) A USB Device
5) The correct USB cable for
6) Drivers either from the OS and/or the peripheral
my Computer Support USB?
There are two
programs available to check if your system is USB ready. Although,
neither of these programs is a guarantee that your computer will provide
trouble-free USB, both provide good indications of capability.
the USB Host Controller
host controllers are NOT created equal. You
should identify the USB host controller type so that you will know how to proceed
if you have problems.
For a “How To”, go here:
the Device Manager / Windows Safe Mode
initial installation problems to suddenly not working USB, cleaning up the
Device Manager in Safe mode is the first step in Win9X troubleshooting.
Many hardware related problems in Windows can be traced to ghost
and/or duplicate device entries. Obsolete
and/or duplicate devices can ONLY be seen and removed from the Device Manager
while in Windows Safe Mode. For a good “How To”, see here:
Common BIOS Problems
Problems are the result of improper settings in the BIOS.
To achieve proper USB connectivity the BIOS needs to be a properly
Enable USB in the BIOS
USB is often disabled by Default
in the BIOS. To enable USB in the BIOS one or more of the following
statements must be true.
If there are NO references to USB
in the BIOS setup, your BIOS Version Needs To Be Updated.
The BIOS version does NOT support USB.
motherboards, even those with USB pinouts (AT Style) almost always
require a BIOS update to achieve proper USB connectivity. Generally, a
BIOS date of June 1998 or newer is required for Win9x systems. A BIOS
date of October 1999 or newer is usually required for systems running Windows 2000.
New Operating Systems require new BIOS revisions.
BIOS Help Links
Agent - Free Software Reports Your BIOS Details and Configuration
- Good Information and Help
- Small DOS program that identifies the BIOS and motherboard - Program is in
German but, you'll get the idea
Wim's Bios Page -
BIOS Download Site - Listed by
updating the BIOS can render a system inoperable and unbootable. Follow
ALL manufacturers instructions carefully when updating the BIOS. Clear
the CMOS with the jumper (see manual) and reset all BIOS data before
rebooting to Windows.
BIOS settings Effecting
BIOS settings that effect
the operation of Universal Serial Bus are shown optimized for USB. The
BIOS settings that effect USB performance are:
Aggressive memory settings
Lack of usable IRQs
Play OS – Disabled
(Socket 7 based) systems may require this option to be Enabled to allow Windows
Steering to operate correctly. Toggle ON or OFF as your system requires.
Assigned – Auto
Management – Disabled
Operating System should control Power Management.
ACPI - Disabled
- ACPI enabled in the BIOS is the source of many USB problems. If you are
having problems with USB, ACPI should be disabled. Unfortunately, simply
resetting the switch in the BIOS may not be enough. Normally, a reinstall
of the operating system will be necessary. Remember to backup your data
before you reinstall the OS. I recommend a clean install to a newly
formatted hard drive.
Keyboard – Enabled or DOS
IRQ for USB – This setting varies by motherboard type.
The “rule of thumb” is, Enabled for Win2000 and Disabled for Win9X.
Try both settings if you are having problems.
are installing USB for the first time a BIOS update may be needed, especially if
your motherboard is vintage 1996-97. The
leading cause of USB failure in these motherboards is a BIOS version that
predates Win98, June 1998. If you
are unable to update the BIOS to June 1998 or later, your chances of installing
correctly working USB is greatly diminished.
information on determining your motherboard type and updating your BIOS go here:
have identified your motherboard, go to the manufacturer’s web site and check
for a BIOS update. Most Mainboard
manufacturers are listed here:
Back to Top
installed IRQ Steering is critical to correctly working USB.
If IRQ Steering is disabled the likely cause is improper BIOS settings.
See the section on BIOS Settings. To
see what properly installed IRQ Steering looks like, go here:
Conflicts with USB
information to the contrary, USB does NOT like to share its IRQ with another
device, (IRQ Holder for PCI Steering is not considered another device).
is sharing its IRQ with Audio, Video, NIC or Modem you will very likely have problems with
(All OS except WinXP)
many IRQs as possible in the BIOS. A
good place to start is COM1 and/or COM2 if you have no external serial device
attached to your computer. (i.e Serial Mouse or Digital Camera)
If you are using a USB printer you can also Disable the Parallel port.
disabling devices in the BIOS, you must boot into Windows Safe Mode and delete the device from the Windows
Device Manager (Win95-Win2000). If the device is not
removed from the Windows Device Manager while in Safe Mode, Windows
will continue to recognize the device and assign it an IRQ.
peripheral cards to other available slots is also an effective method of
resolving IRQ conflicts. Each PCI slot is assigned an IRQ by
Default. Some PCI slots share an IRQ with USB. Avoid those
slots. Check the Mainboard Owners Manual for this information and use it
as a guide to avoid IRQ conflicts.
freeing IRQs in the BIOS does not produce the desired result you can manually
assign an IRQ for a conflicting device in the Windows Device Manager while in
Safe Mode. If manually assigning IRQs you will need to Disable
Plug and Play OS in the BIOS, otherwise Windows will continue to override the
BIOS assignments. If the OS is installed in ACPI mode, IRQs assigned in
the BIOS will be ignored by the Operating System.
still cannot isolate USB to it’s own IRQ, changing the I/O range of USB
1. Boot to BIOS setup and disable ACPI
2. Go to the "Integrated Peripherals" section and disable both serial
ports if you are not using them.
3. Go to the "PnP/PCI" section and disable "PnP OS",
"Auto" and "Reset Configuration Data (aka ESCD Update)". The last is a
momentary switch and will be disabled each time you return here. It releases the
BIOS lock on IRQs and lets Windows take over.
4. Go to the Power Management section and disable all BIOS control of power management.
5. Boot DIRECTLY to Windows Safe Mode. Remove all USB
software in Add/Remove Programs. Open Device Manager. Remove the USB root hub
and host controller *in that order*. Remove all USB drivers. Look for duplicate
or erroneous drivers and *remove them all*. Windows will reinstall genuine
6. If you have any SB16 emulation drivers, disable them in the hardware profile
(do not remove). These are DOS sound drivers and most don't need them.
7. While still in Safe Mode, go to System Devices and disable Advanced Power
8. Lastly, remove the drivers for sharing devices. Windows should reinstall the
Unplug all USB devices except USB
Keyboard or Mouse before rebooting to Windows Standard Mode.
At this point you have freed up 2 or 3 IRQs and
reset Windows IRQ assignments. You can reboot and reinstall your devices *as per
NTKERN.VXD are most often caused
when USB cannot negotiate an acceptable IRQ address. To correct this you
will need to free some IRQs in the BIOS and then delete the device entries
from the Device Manager while in Windows Safe Mode. (See the IRQ Conflicts
To Manually reinstall a
corrupt VXD File
(For experienced users
only. Backup your data in case a reinstall is necessary)
Specific VXDs are in the CAB
files on your Windows installation CD. VXD files are OS specific.
CAB File Locator
Using Windows Explorer open the
Win9X folder on the Windows Installation CD. Right click on the
appropriate CAB file (from above).
Highlight the correct VXD file and
extract it to the following Windows folder on the (x) drive that Windows is
Win98 & Win98SE
Close Normally and Reboot.
Try the installation again.
Code 2 /
The NTKERN.VXD device loader(s)
for this device could not load the device driver. (Code
USB Host Controllers
(USB Problem Devices)
and older Intel USB host controllers account for the bulk of problems when a
user is trying to establish USB connectivity for the first time.
and Tricks for the most popular non-Intel USB host controllers is here:
Back to Top
Intel USB Host Controllers
1996 - 97 motherboards, even those with USB pinouts, almost always require a BIOS
update to achieve proper USB connectivity.
BIOS versions dated before June 1998 usually do NOT provide
acceptable USB support. If the BIOS
properly supports USB, installing a motherboard cable assembly will allow you to
take advantage of the onboard USB capability of the motherboard.
Go here for information on USB motherboard cable assemblies.
Belkin Model F3U001, Motherboard Cable Assembly has been tested and
approved by USBMan for use with most 2 x 4 and 2 x 5, USB pinout arrays.
Go here for more information:
to USB by PCI/USB upgrade card is a recommended solution for systems with
non-functioning onboard USB host controllers. A list of tested and approved upgrade cards
Properly Installed the USB
upgrade host controller should share the same IRQ as the onboard USB host
controller. Check the motherboard manual or Manufacturers
Web Site and install the new card into a PCI Slot that shares it's IRQ with
USB. DO NOT disable USB in the BIOS as the upgrade card may not work if
sure that the new upgrade card is fully seated into the PCI slot. Do not
close the case until you have established proper connectivity.
on Lucent USB Host Controller
Windows 98 & Me Error Message
USB is a connectivity solution for
peripherals that are in close proximity to the USB host controller (computer).
Cable length must conform to the
USB 1.1 Specification.
If your cable is damaged or lost,
purchase a certified USB 2.0
cable of the same length or a replacement cable from the manufacturer. USB
2.0 Certified Cables are the highest quality USB cable available and should work
with almost any device except some scanners and cameras that require special
Extending USB cabling to a length
that is not supported generally results in device failure or unknown device.
Extended length can be achieved by
the use of an "active USB cable" or the installation of a powered hub.
USB over IP Remote I/O Concentrators
can be used to extend cable length far beyond the
USB 1.1 Specification
USB Hubs connect to the
onboard USB host controller and provide additional ports for
connecting USB peripheral devices. A hub does NOT add
additional USB bandwidth to the system. Scanners, web cams,
digital cameras, card readers and docking bays are high bandwidth
devices that are often not properly supported through a USB hub
connection. If your USB device is NOT recognized or does not
work properly, try connecting it to an onboard port. High
bandwidth devices usually require additional USB bandwidth. If
you plan on connecting additional high bandwidth USB devices to your
computer you will need to purchase and install either a PCI/USB card
(Desktop) or USB CardBus (Laptop) adapter to increase the usable USB
bandwidth on your system. There is a list of Tested and
cards in the USB Problem
Solver under Tools.
A USB network can NOT
be established by connecting 2 computers using a standard A-A USB
cable. Connecting 2 computers using a standard A-A USB cable
will damage both USB ports, the USB peripherals they are attached to
and the motherboard. To establish a USB network you MUST
purchase either a USB Direct Connect device or a USB networking
kit. It's always cheaper and often just as easy to use a pair
of PCI or ISA NIC cards.
- Paul Rollins