Win7 not loading

I built this computer over 6 months ago, after several months of troubleshooting and many thanks to those on TH, this computer has been rock-solid over two months. Specs are below:

i5-2500k (@stock)
asus p8p67 m-pro
corsair ax850
gskill 8gb (2 x 4gb) 1600 MHz CL8
crucial 64gb C300 ssd
seagate 1tb 7200rpm
CF'd XFX 1gb 6950's oc'd 840/1325
sony optiarc dvd r/rw
LG bluray r/rw

Now the problems... A couple of nights ago I put in an extra fan over the gfx cards, because they were heating to ~100C under load. They ran fine, but the extra fan dropped the temps 15C. After a BF3 session, the PC was turning off when I got up and tripped over the PC in the dark   knocked over the PC and the PC froze in win 7 while shutting down. The PC gave a BSOD after a reboot, but after that I was able to play BF3 fine. Earlier today, I turned on the PC and sensed something was off. Checked computer properties and saw only 4gb of ram. PC was opened and reseated the ram. Then the problems set in:

the PC booted, checked the UEFI bios, everything look kosher, saved and reset
PC booted, and win7 did not load (ie no logo). I've rebooted my system checked my boot order, but the OS still does not load.
rebooted several times and still no win 7 logo

Any ideas?

Right now I'm considering a clean install... and some gaudy blinking LEDs.