Dual 9800gx2 problems

I am having problems with my 9800gx2 setup, Whenever I enable quad sli I have tons of problems. Whenever quad sli is enabled(with nvidia control panel) and I boot my computer half the time I will get a no input signal. My computer starts to boot then beeps and a blue light will come on either of the cards inside the case. If my monitor is not plugged into the correct card(card which light turned blue) I will get no input signal, If it is in the correct one windows will start up and then begin to blink black and in and out multiple times only after windows is booted and loading my programs. The system becomes extremely touchy once the blinking starts blue screening or just giving the no input signal after the computer has been on for about a hour. Also under the nvidia control panel settings the card that oftens works the most(bottom card in case) has the setting to [enable multi-gpu mode] while the top card gives the option [enable quad-sli] . Here are my specs any help would be greatly appreciated.

Video cards- (2) Xlr8 9800gx2 1g memory
Memory - 4 sticks PNY XLR8 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400)
mobo- Asus P5N72-T Premium
cpu- Intel Core 2 Duo E8500 Wolfdale 3.16GHz 6MB L2 Cache LGA 775 65W Dual-Core Processor
Sound- Creative Sound Blaster X-Fi XtremeGamer 7.1 Channels 24-bit 96KHz PCI Interface Sound Card
Power- 800 watts
default fans


I am also completely lost with bios settings so the settings are probably default.

Might need a bigger PSU, depending on the rest of you're system...