Monitor turns on and off repeatedly after booting computer!

[C O Y O T E]

Hey there!

I was going to bed yesterday, and just shot off my PC, letting it install some Windows updates.
I wake up this morning, turn on my computer, and the bootscreen shows up fine, it seems to load fine, but when the bootscreen disappears the screen just turns on and off repeatedly, very quickly. As in, the screen actually seems to switch off. It doesn't stop, rebooting or unplugging everything doesn't make a difference. If I try to go into repair mode it tells me Windows couldn't find anything to repair.

When I try going into Safe Mode, I just get a black screen. The screen is on, though.
What's going on? HELP.

[editline]21st April 2014[/editline]

I'm pretty much 100% certain this is a Windows Update issue. I found a system restore point from both yesterday and 3 days back. The one from yesterday made me boot fine, but it started installing updates. When it finished it rebooted and the blinking screen started again.

I now restored the one from 3 days ago, and my computer boots up perfectly fine.

LESSON LEARNED: NEVER USE WINDOWS UPDATE EVER.