Whenever i upgrade my 98SE computer to windows 2000,it says that it can not transfer files to the hard disk,i have plenty of gb left on the drive

So don't upgrade.
This is only the beginning of troubles. Then during the upgrade you see other hassles, you see crashes and instability during operation.... its too much bother.

Just backup all your required files (from C: to D: or something..) and do a clean-install by booting up from the win2k CD.

ROTFLMAO
That DOES cut right to the chase prathapml

a clean install with be the best thing since sliced bread,just make sure you have enuf space plus if you upgrade, there are files n such that are left from the previous windows install,on a clean install, you start out fresh instead of having old, useless folders from your previous installation,it is kinda fun when you do an upgrade, you get to delete the old stuff like the older windows directory can be deleted and windows 2000 calls it winnt instead of windows,if you know the difference between oses,you can actualy delete alot of stuff and then you would be clean except the registry but using an app called crap cleaner can help you big time.and using xplite can help you too.