Boot to the Windows 2000 CD and choose "R" for a Repair.
This takes you to a screen that gives you two more
choices, the Recovery Console or a Repair Installation of
W2K. Choose "C" for Recovery Console. You should be
prompted for the operating system to boot to and the local
administrator password. If you are not prompted for a
password, then there is no access to Windows at all. An
example of a good hard drive but a destroyed file system
is when you get an "invalid boot" message at boot time,
and you're unable to view directory info at the Recovery
Console. At the Recovery Console prompt, run:
CHKDSK /F /R
Since you're booted off the CD, not the hard drive, it
will run without a reboot.
If it refuses to run, then you probably have a hardware
fatality.
Reboot to see if this fixed the problem.