computer won't boot, blames keyboard, blames hard drive

[soah]

I was playing poker this evening and just after closing down my tables, my mouse and keyboard stopped responding. They both plug into USB ports. Some popup messages came up saying that there was a failure with a USB device. The problem didn't fix itself on its own after a couple minutes and I couldn't do anything, so I pushed the power button to shut it down and reboot.

Upon rebooting, I get a screen with the following message:

Phoenix ROM BIOS PLUS Version 1.10 A07
Copyright 1985-1988 Phoenix Technologies Ltd.
Copyright 1990-2006 Dell Inc.
All Rights Reserved

Dell DXP051 Series
BIOS version A07
www.dell.com

Keyboard failure.
Drive 0 not found: Serial ATA, SATA-0
Strike the F1 key to continue, F2 to run the setup utility

The keyboard doesn't respond. Usually there would be a green light lit up (for num lock or whatever) but it's all dim.

I plugged the mouse and keyboard into my laptop and they each functioned properly.

I did some googling and there was one suggestion that the hard drive might have become disconnected... and that seemed easy enough to check, so I fiddled with that a bit and the next time I turned the comp on, it still gave the "Keyboard failure" message but not the next two lines, and Windows booted up. But neither the mouse or keyboard worked (the green light did not come on either). I thought perhaps I'd plugged them into different USB ports since I hadn't really paid much attention to their arrangement, and perhaps they just weren't recognized... turned it off, turned it on again, and this time when Windows booted up, it went through a self-check thing where it scanned the hard disk and then went through a ton of lines of "Recovering orphaned file [something] to [something]". It said some other things too but it scrolled so fast I couldn't read them. This went on for several minutes, and then it said something about having corrected some problems, and rebooted. And now I'm right back at the same error message I was getting earlier, which I put in italics above.

I tried putting the Windows XP CD in the CD drive but it changed nothing (and by that I mean it's not getting to the point where Windows boots anyway so it ignores the CD).

I have a Dell XPS 400 that is 1.5 years old running XP Media Center edition. It's no longer covered by warranty.

After having written all this, I took out the Windows CD, tried turning it on again, and Windows booted up but once again I can't use the mouse or keyboard. I now unplugged them both, and got a message:

USB Device Not Recognized

One of the USB devices attached to this computer has malfunctioned, and Windows does not recognize it. For assistance in solving this problem, click this message.

This is one of the same messages I was getting earlier.

So anyway, turned it off, and now once again I can't even get Windows to boot.


I know very very little about how computers work or how to fix them... but if I'm given specific instructions on what to do I can do it. From what I've read, the problem is likely something with the motherboard. However, I have no idea how to identify the problem or fix it.