Weird "Greyed Out" Screen

Hi Everyone! Got a weird issue in today. We have this Mid-2010 MacBook Pro 17, that was brought to us with the customer stating it had a virus, and would not turn on.

Turning on wasn't much of a problem, although I had to hold down the power button for a few seconds before it kicked.

Once it was on, it seemed to run OK. I made a few clicks, checked a few things, and had to run out to another client.

When I returned several hours later, it had a black screen, and wouldn't respond to any input, but the machine was quite hot in the area above the keyboard, between the keyboard and the LCD, on the left side of the machine. Eventually I pulled the power cord and held down the power button for a minute, and then I was able to start it up again, but the screen came up like this:

No input is accepted at all, and the only thing it gives me the opportunity to do is hold the power button down to shut it off.

Who's got the great ideas as to what might cause this, before I start chasing down weird electrical gremlins that might be making it happen?

Several months back we wiped this same machine clean and reloaded it, and at that time, the client did report crying over her daughter spilling milk in it, but long before we ever touched it. (So it's definitely not still wet, but may be shorted somewhere.)