Sorry, I was very wrong -- it's a Dimension 8400 (I guess it matters if I get the name and numbers right). It's a desktop with an external keyboard. Also, now that I think about it, there was a crunching noise when I started the computer up a few times before I started having the problems.

The links you provided seem like they would help if I could get the computer to respond to the keyboard and if it would actually boot up in safe mode. But, it just freezes after the "Seconds until Windows starts:" message just ticks down to zero.

Does it sound like I need to install a new hard drive? Would a bad hard drive cause the keyboard to no longer power up (that is, none of the lights on the keyboard go on and the computer doesn't seem to respond to key strokes). Thanks again for any help.