sudden crashes

[dbclinton]

I transplanted the HDD from my Edubuntu 10.10 server into a different
box and the sudden reboots seemed to have stopped. My guess (based on a
couple of suggestions from this list) is that the culprit was a flaky
power supply.

Now, however, I have what seems to be a rerun of an old problem from
8.10: when a user logs out of the server, we lose the monitor entirely
with no apparent way to get it back short of rebooting. The clients are
all still happily chugging away no matter how many users login and out,
but we lose access to the server machine.

I tried SSH-ing to 192.168.0.254 from a client's terminal, but I wasn't
allowed to run GDM.

Any ideas?

By the way, the server is a Compaq Evo P4 2.4GHz with 1 GB RAM

Thanks,

David Clinton