Negetive Effect

Sounds like he may have accidentally engaged some Universal Access settings. Have him do the following:

1. Open System Preferences and go to Universal Access prefs..
2. Under the "Seeing" tab, make sure the Display settings are set to "Black on white." "White on black" will invert the screen.

 

[ctrl]+[option]+[command]+[8]

try that.

 

Hmm.

If possible, set up a new user account and see if it affects that one as well. If it doesn't, you're probably dealing with something with his user account versus a system-wide issue.

My guess is that it's a corrupted preference file or something. That sort of thing can cause all kinds of weirdness.