Need Help with USB device problem: "Unknown Device"

Guys i need your help, a neighbor of mine went away on for 2 weeks and requested that i break down her computer so she could have her floors redone while she was away.

When we put everything back together and now we have a problem.

3/6 of her USB Devices do not work and only show up in the Device Manager as "Unknown Device"
not working are : Logitech webcam, WD passport HD, Canon camera.
working are: Microsoft ergonomic keyboard, Logitech wireless mouse, Canon printer.

I've tried uninstalling the root hubs, uninstalling the "unknown devices", updating all device drivers, rebooting in safe mode, use system restore (no system restores present from before she went on trip) Disabled Windows ability to save power by turning off the USB root hubs, disable anti virus, disable firewall, switching what devices are plugged in where. And maybe a few more things that i can't think of right now.

Specs on the machine are:
MFR: Gateway
Model: MFATXPNT ESX 500 P04
Age: 2002 (yeah it's an old ass machine)
OS: Windows XP Pro SP 3

I am completely out of ideas, does anyone have any thoughts on how to fix this?

Is it always the same three devices that don't work? If you swapped out one of the working ones for one of the not-working ones does it then work (in other words I would try to find out if it is the USB port or the devices).
I would buy a cheap USB add-in card if you can isolate it to that, it's 10 year old hardware no telling what dust got shifted during the tear-down.

Do the devices work if you plug them into a different computer? (Preferably yours, to help rule out some kind of virus or trojan that's messed up the USB stack.)

I will be taking some of my USB devices over to her house today to check it out, but so far: It is always the same three devices that don't work but a different USB device (i.e the keyboard) in the same port does work. And i took the WD hard drive home and plugged that into my system and that does work on mine. So the problem definitely seems to be in Windows on her machine.

Think i should try a Bios update?

What about power? Do those possibly need higher powered ports? Are they plugged in how they were initially?

I know some USB ports don't have enough power to run things like HDs on their own.

All devices before the trip worked just fine, so i don't think power is the issue.

I'd probably try scanning for malware, in case a virus or trojan is messing with the USB stack to do surveillance.

Scanned with Malware nothing detected also ran CCleaner and it fixed a bunch or registry issues but no dice on that either. Installing any/all windows updates now and seeing if I get really lucky on that front. Any other ideas?

Sweet Jesus I figured it out. Can't believe I didn't think of this sooner. What was the one thing that had changed from before the tear down to after. The location of the printer and the 10' USB extension cord I got from frys. Bypassed that ad poof all the other devices came back on. Weird you'd think a faulty cable would cause the printer to stop working and not all the other devices.

Huh, I should have asked you what was different... I just assumed you'd set it up the same way.

Sorry about that. If I'd had my brain engaged, it might have saved you some time.

That's a nice happy ending.

As a quick follow up I purchased another cable and tested that on the system and got the same result so either Belkin makes crappy cables or there is enough signal degradation in a 10 ft cable to cause the problem.

Might not be signal "degradation" but USB power requirements, maybe? I.e., longer cable requires more power to reach the end and maybe the USB host/controller on the mobo was already at its limit before.

The only thing I can suggest (if this is indeed the case) is buying a PCI USB card and plugging in two or three of the devices on that instead.

Well client is happy where the printer is now at, she is using the table where the printer used to be as a spot for photos now and the printer is now hiding all of her cpu cables so win win i suppose.

I think Duoae might be right. She is probably at her limit with the USB devices and trying to send power down a 10 foot cable is to much.

Something else you can try is buying one of those powered USB hubs and seeing if the extra power from the hub helps with the 10 foot run. Maybe even plug some of the other stuff in the hub as well, so as not to put to much strain on the system.