Following an upgrade with Windows XP SP3, my USB devices were no longer detected. In My Devices, the normal 3 instances of USB root hub were gone, causing the other USB controllers not to load. Solution: remove upperfilter and lowerfilter keys in the registry. Be sure ONLY to do this for the keys that refer to USB devices, NOT to other devices.

Was it beta SP3, or the officially final SP3, now available at Microsoft Update (at least it is if you are setting up Windows from scratch again)? I had no problems with the latter situation recently. Of course, I loaded the main chipset drivers etc. after Setup was finished, before I loaded SP3.

It was the official release of SP3. Although I have no doubt about the temporal relationship between the upgrade and the USB-error (it happened immediately at the system reboot after SP3 was installed), this does not mean that the same could not have happened with any other install. I've since seen several - older - referrals to code 39 errors and Upperfilters-keys in the registry and the general idea I get is that these keys sometimes can become corrupted on any manipulation of the registry. Interesting to note is that a system restore to a date before the SP3 install, did NOT solve the problem

What was the software situation on your computer before you installed SP3? Did it have the original Toshiba software installation with previous Microsoft Updates already installed, or had you re-installed Windows from a regular Windows CD and it had previous Microsoft Updates already installed, or what? I am presently updating a computer I am working on for a friend of my brother's, and I see Microsoft Update wants me to install SP3 despite the fact it has virtually all previous updates already installed.

Is was an original Toshiba Windows setup, with all automatic updates performed since install (2 years ago).