Thanks to all
Got the disk out, no changes (had thought of it indeed). The LED keeps on blinking.
The monitor seems to be OK, it just says "power save mode", "activate using PC" (same behaviour wether PC is ON or OFF).
On the PC the power button lights up as do both CD and DVD drives. The keyboard LEDs flash on power-up and the optical mouse is active.
Guess someting IS fried in the PC itself. I'll have to mail the tech support.