I've looked on Google - some other guy has same problem but no resolution.
The bastard engineers were replacing the DVD-ROM I mentioned in another thread I had problems with. Somehow he's managed to cause this ****ing annoying "Frequency Over Range" error message appear on my screen (I can't use anything). I reinstalled Windows and it logins fine BUT I can't access any resolution over 1024*768 otherwise the error message appears again - the screen will turn off (although the PC is still running) then if you type a key on the keyboard, the screen returns to its previous state and back to 1024*768. LIKE WTF?
This seems to suggest refresh rate - but the same refresh rates I had before the engineer buggered it all up don't work (how can they work before but not now) and it's not high either (70Hz) - grrrr!
Pllllease help thanks