About 2 weeks ago, all usb ports on my computer quit reading devices. If a device is plugged in it still powers up, but the computer doesnt see it. I have updated BIOS, updated drivers, rolled-back drivers, set drivers to "standard", rolled back SP2 updates (XP Pro), re-installed updates, etc. rebooting and retrying devices with each change, all with the same result. USB ports are both 1.1 and 2.0. Some came "installed" with the machine, 2 are on a 2.0 card I installed myself. All ports worked for several months, again until just about 2 weeks ago when all quit in the fashion described. Suggestions? Please?