startup problem

I have Windows XP Home.

 

I haven't been able to logon because the windows xp login screen didn't show my user accounts.  I tried c/a/d 2x and attempted to logon as administrator but this didn't work.  Then I tried F8 and chose safe mode.  As windows xp home loads I get a message box that says "lsass.exe - system error, the specified Domain did not exist."  When I click ok, the computer restarts and I get the same error message.  Is this a virus?

 

By the way, I added a new printer (HP 2610) a couple days ago.  I printed a few things without any problems, then shut down my computer.  When I turned it on the next day, the problems began.  Any help would be appreciated.  Thanks.