CD-Rom Drives dissapearing

So my dad has a computer issue, about a few weeks ago, he spilled some water all over his keyboard, no problems occured.. about a few days later, he was watching streaming video off some car site, and his pc froze. The DVD-rom light lit up, and that was that, restarted, problem fixed. Now, tonight, he was playing bejeweled, and it froze again, DVD-Rom light lights up, and crash. no blue screen, no nothing, just frozen, so he restarted again, and lo and behold, his CD writer doesnt want to open anymore.. his DVD-Rom opens, but doesnt read any disks, in 'My Computer' it doesnt show the disk drives, neither does it show it in the device manager. We tried a system restore to a month ago and it didn't fix the problem.

Any ideas?

Jam it back in, in the dark.