Here's the problem-
I've got an Optiplex 740 running Windows XP SP3, and it's joined to a domain-- after you power it on, it goes through POST, goes thru the Windows XP logo booting screen... the screen blanks... mouse pointer shows up... then NOTHING. You can move the mouse, but there's no window that prompts you to hit Ctrl-Alt-Del to login... nothing.
Tried rebooting in safe mode, same thing-- just get a mouse pointer, no prompts for user login information. Safe mode with command prompt? Nope, just get a mouse pointer.
I grabbed the Windows XP SP3 CD to try a windows recovery, but it keeps bluescreening during the attempt to enter the recovery console.
24 hours of Memtest+ show no apparent issues with the RAM.
How can I proceed in getting this thing to accept user login again?
Three hours of troubleshooting later, we just queued up the bootable DVD with the XP image from Dell ImageDirect. There comes a point where you just have to say move on...
Thanks for the suggestions, everyone. My best guess is corrupted sectors on the hard drive.