Here are some things to try. Try to uninstall SharePoint and then try to
reinstall it again, or try a restore. Try to restore  the database on a
machine with Windows 2000 SP2 and SharePoint SP1, or original SharePoint and
then perform the service pack upgrade(s) afterwards. Also another thing you
can try is to pre-create the workspaces and then try to restore the
database. Make sure that there are no red stop signs for the workspaces
(you can see this in the IIs MMC Console, to correct this, restart the IIs
Admin services thru the services in Administrative tools).

I had a lot of problems trying to restore a database back to the same
machine after a disk failure. I had SP3 for Windows 2K and SharePoint SP1
installed on the machine  before the crash and when I tried to restore it
back on a a clean installation of Windows 2000 SP3 and SharePoint SP1, I got
soo many error  messages. I tried multiple different methods to restore it
but the one that worked out was Windows 2000 SP2, SharePoint SP1, then do a
restore. This will fail, so reboot and then run an uninstall. After
uninstalling, reboot again and then do a re-install. After the re-install
proceed with a restore and then the isntall of Windows 2000 SP3.

This should work, but you may need to try different things based on your
particular error problem.