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USB Troubleshooting Bible - Advanced

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USB Troubleshooting Bible - Advanced
While the following techniques apply mostly to Win 9x, some of the concepts 
(such as the BIOS Settings) may also help resolve issues in Win XP. This info
is offered as a courtesy on an AS IS basis and VTB makes no warranties and
bears no responsibility for issues that may result for your use of this info.

USB Connectivity Requirements:
To achieve proper USB connectivity six basic 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 the device
6) Drivers either from the OS and/or the peripheral maker

Does 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.

- Intel USB Check:

- Entrega USB Ready:

Identify the USB Host Controller:
All USB 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:
Host Controller PCI / USB - How to identify - Win9X

Cleanup the Device Manager / Windows Safe Mode:
From 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:
Clean-up Device Manager in SAFE MODE - Win9X:

BIOS: Common BIOS Problems:
Many USB Problems are the result of improper settings in the BIOS. To
achieve proper USB connectivity the BIOS needs to be a properly working

BIOS: 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.

BIOS: USB Keyboard - DOS or Enabled (Even if you have NO USB Keyboard)
Legacy USB Support - Enabled
Assign IRQ for USB - Enabled (Some combinations of OS and BIOS version
require this setting to be Disabled).
If there are NO references to USB in the BIOS setup, your BIOS Version Needs
To Be Updated.

BIOS: The BIOS version does NOT support USB:
Vintage 1996-97 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: BIOS Help Links:

BIOS Agent - Free Software Reports Your BIOS Details and Configuration

BadFlash - Good Information and Help

CTBIOS - Small DOS program that identifies the BIOS and motherboard -
Program is in German but, you'll get the idea

Wim's Bios Page - BIOS Help Site

USBMan BIOS Download Site - Listed by Manufacturer
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