Windows XP has a rollback feature (Windows restore or something like that). Set it back a few days befor the trouble started. Windows update is nice for Windows patches and security fixes, but never use it for driver updates. It installed drivers for my ATI TV Wonder VE (TV tuner card) and it turned out they were for a video in card from another company. I used the Windows restore, but later found out I could have manually forced the ATI drivers to install over the other one to fix it.
AMD Phenom II x4 945 3Ghz | ASUS M4A77TD | 2X WD 1TB SATA 2 hard drive | 2x2GB Corsair XMS3 | nVidia GeForce 8800 GTS | ATI TV Wonder Theater Pro 550 | Antec P-160 case | Antec 650w Earth Watts | LG Blu-ray Super Drive | LG DVD RW | Windows 7 Pro