|Hi Richie, (as partially suggested above) I would:-|
a) with the power off, disconnect/reconnect the monitor interface cable (possibly both ends) and power cable.
b) if no joy, try another monitor.
c) please advise, what if anything appears on the monitor when it flashes.
d) if 'No SIgnal' is appearing on the monitor this suggest it is ok and there is a simple interface cable connection problem. Also there may be a strap on the mobo for off or onboard graphics.
Hi Phil, before trying another card, I would have advised, if present, reseat the graphics card (by removing/replacing 2 or 3 times) in its own slot, next try in another slot.
However in this instance the op advises the problem still occurs when using onboard graphics. Regards - Mike.
Good Luck - Keep us posted.