Did you try safe mode? Or can you get into the BIOS at all? (If the BIOS doesn't come up at all, I'd think of a hardware problem rather than a driver one. I know I often got the blank screen with a bad video card driver.)
Could be the motherboard. Also could be the RAM I had a similar problem on my old computer. (except instead of the blinking, it'd freeze up at the startup screen). I'd suggest taking out the hard drive and either getting a nifty external case for it or hooking it up as a slave to pull your stuff off, because if you need new hardware, you probably need to reinstall. Also any unusual noises from the HDD, or is it spinning up at all? Also could be the CMOS battery.
One final idea: A screwed up monitor. But I don't think the blinking cursor would work for a ruined monitor.
But take this one thing at a time. Don't panic, that's the worst thing you can do.
Edit: Sorry, my words can sometimes get into a jumble. To make this more clear, here's the things I'm suspecting --
- Bad drivers
- Damaged motherboard
- Damaged RAM
- Damaged hard drive
- Dead/dying CMOS battery
- Ruined monitor
Things to do:
-- Check to see if the BIOS will go in at all
-- Listen to the drive to see if there's funny noises or if it spins up at all
-- If files are important, pull the drive out to get the data
