I just installed 8.2 yesterday on a generic P4 that I built. I've been preparing for an Oracle9i database install, and all of a sudden

when I do a Logoff User and select "switch user", my screen flickers a few times and then acts like it has no signal, but the PC is still up & running (based on what I'm hearing). At this point my only options appears to be to hit the reset button and reboot.
I believe this user switch worked at first, but I haven't done much except create a few users & groups and directories for the Oracle9i install.
Any ideas?