Their alot of bugs in Windows 2000. Do you have all the update? I think that their up to SP3 on Windows update. SP3 fixed alot of the bugs. How much ram does your PC have? Windows 2000 uses alot of ram. Have you checked to see what programs are starting up when you boot? Window 2000 doesn't have msconfig, but you can use this program
Start Up Panel its a reay good program.