install problem stuck on

I upgraded win 98 to win 2000 prof.
There was a problem with the installation so I tried to reinstall it, Instead of reinstalling it, it installed a new version. So now I have 2 copies on c drive. The first didnt work the second did. To get rid of the first I booted from disk and went through the install process to uninstall it. The problem is that when I got to the add key screen it gave me an invalid key error. It is now stuck in install and I cant get out since it just asks for the disk again when I reboot. NOw I am stuck and cant get in at all.