You haven't given any history of how it all happened. Perhaps I am right in assuming that your computer was running fine earlier.
Most likely the problem is due to virus or malware. If you have run your Anti-Virus and Malware Programs and the problem did not get resolved, then the best course would in my opinion be to reinstall Windows.
System Manufacturer/Model Number Custom Built OS Windows 7 Pro with SP1 32bit Motherboard Intel D845GVS1 X86-based PC Memory 2 gigs of RAM Graphics Card Intel(R) 82845G/GL/GE/PE/GV Graphics Controller Sound Card Realtek AC'97 Audio Monitor(s) Displays Samsung SyncMaster 931BF Black 19" LCD Monitor Screen Resolution 1280X960
Keyboard COMPAQ Standard PS/2 Keyboard Mouse iBall Laser Precise Speedster Hard Drives 1. SAMSUNG SP0822N ATA Device ~ 80 GigaBytes
2. Seagate FreeAgent Go USB Device ~ 500 GigaBytes Internet Speed 4 mb/sec
Well, I uninstalled a file and also updated my windows at the same day, so i dont know the real reason, ive tried using event viewer and saw some errors, fault application name is explorer.exe event id 1000, how can i resolve this?