Seems to be that time where a reinstall of Windows would be good.
However, some dont have that option, so download and install all new drivers for your computer > display, sound, modem, chipset, nic, raid, etc. Anything that uses a driver. (VIA 4in1, etc)
Reboot into safe mode. GO into device manager and remove all IDE devices (hard drives/CDROM/CDRW/Zip). Reboot. If this doesnt work, reboot to Safe mode and and delete your IDE channels. Reboot.
Have you been playing with TweakUI?