windows 2000 act up!!!please help!!!!!!!!

I dont know what happened to my system. Soon after i start win2k and when i try to open "My Computer" it takes a long time to open. In fact it takes a long time to open any program as soon as i boot to win2k. I tried disabling all start up programs and even uninstalled my antivirus software. But the problem still persists.
Can somebody tell me how to get about this problem? Please!!!