Did my graphics cards just die? HDMI Signal loss

So recently just rebuilt my setup with some newer components and had it running for couple of days then i went to load up Dead Rising 2 and HDMI signal drops now i have no signal whatsoever.

Have tried diferent cables, different monitor, vga cable, pushing graphics cards in, clear CMOS but still nothing.

New components are not the issue as i was playing Dead Island Riptide yesterday morning for 7 hours straight and pc has been running for couple of days, all i changed was relocated everything to a new case and upgraded my cooling system with new pump, res, rad, fittings.

These are the main components Asus 27" 3D LED Monitor, Gigabyte-990FXA-UD3, Watercooled AMD FX8350, 2x Watercooled MSI GTX580, 16gb Corsair Vengeance RAM, MaxRevo 1500w PSU then all my pumps res etc.

Anyone have any views into why this happened? Also because of the state of my system its extremely hard for me to pull out cards and test them on thier own or test other cards as i have to drain my loop everytime i need to remove or replace a card, so i kinda want to avoid doing that unless all else fails it might be something im overlooking for monitors as this is the first monitor i've used (usually ran from a 32" led tv until recently)

Any help would be great.

Sorry should have mentioned only have the 27 plugged in, unplugged that and tested the 32 with same result, and yea it boots up even hear the windows login sound so I know it's getting to desktop.

Checked power cables replugged them, tried with bridge off still nothing I also tried with 1 card not powered and bridge off but gave me a post beep, want to try avoids unplugging a card from pcie cause ill have to drain loop to remove a card.

Just finishes work so am gonna try everything again just in case I missed something.

Any other ideas while I'm at it.

U should mention I have a spare gt520 to test and a spare loop I can setup externally but only if ALL other options fail.

PROBLEM SOLVED, headache averted.

So i pulled off my side panels, unplugged both ends of gpu power cables (from cards and from psu) blew both ends out and power slots on cards, plugged them into psu slots (modular) pulled the cards out VERY carefully from pcie lanes (luckily my crystal link didnt slip out) and pushed them back in firmly plugged everything else back in and like magic she booted right up.

Kind of a little sad though would've been a good excuse to justify getting SLI 780's oh well the time will come.

Thanks Solar must not have done a good job the first time round and i thought i better try again if you think a recheck will sort it out. +Rep coming your way buddy

Turns out you were my last rep cant re-rep you till i "share it round" sorry but thanks