My Computer: AMD Athlon 2100+ XP Abit KX7-333 Sound Blaster Live 256 PCI 512 MB PC-2700 DDR 80GB Seagate 7200RPM MSI GeForce4 Ti4200 The Problem: As of right now, the computer will only load my Windows XP Pro when i use either Fail-Safe or Optimized Defaults from the BIOS which sets the cpu as 1500+ (1.30ghz) (lowest value). When i try to select any other value 1600+ to 2200+, the progress of loading Windows becomes very erratic, at times it restarts right after the IRQs display screen while at other times it can reach the Windows login screen, but i have yet able to load my desktop. Also, with fail-safe or optimized defaults loaded, everything seems to work fine except when i try to play any video file, the computer will completely freeze up (must hit reset button), same goes when trying to run a game. Situation Prior: I have had this computer for more than a year and a half without any problems. All this happened after i decided to clean my desk and computer of dust. The computer was turned off and i used my vacuum with the thin plastic attachment to suck up the dust. I did remove the heatsink and fan from the cpu but after cleaning, it was placed back properly. Things I've Done Since: After solving the initial problem of not being able to boot into windows at all, i have reseated both soundcard and video card. I have also reflashed my BIOS to its newest version, completed without any problems. Thanks for reading this and if you have any ideas or suggestions on how i can have my cpu run at its intended speed of 2100+ (1.73ghz) and play video files without freezing the system, it is greatly appreciated!