Thanks for the reply, Dwarf.
Don't think the graphics card or monitor cable are faulty, I mean once I unplug and plug back in, it all works perfectly fine, can still run games etc. without fault. I don't use an adapter, it is simply DVI out from the video card, straight into the monitor.
Tried the second DVI port on the graphics card with the same problem.
Now, as it comes down to drivers. I think I may have fixed it, for now that is... I disabled the driver for the monitor in the 'Devices and Printers' section. But also updated to the latest Catalyst Control Centre and actual video drivers. I did a hot reboot and I could see the logon screen. So which ever one of those two things that has fixed the issue I am not entirely sure.
Thanks again, Martin.
I will keep the thread updated if it happens again after a cold boot. EDIT:
Alright, the blank screen is properly fixed now, after the cold boot it all worked normally.
Now there is just the issue of the Aero effects randomly being disabled after a few seconds on startup...