A plea for help, as I'm drawing a complete blank trying to figure this one out. Came home today to find the display on the Mac essentially unreadable - brightness & contrast both pushed up so high you can't make anything out. It's a software thing - if I user switch to my other half's account, everything returns to normal, switch back to my own account and it all goes haywire again. So definitely not a hardware or monitor fault (seems the cat was sleeping on the keyboard, and whatever combination of keypresses that has produced has been the guilty party). I'm at a loss as to where to start - I've checked under System Prefs, what options there are under Display & Appearances don't cover the problem - anyone able to point me in the right direction?