Turns out one of my 8800GTS cards was faulty, i ended up trying it on one of my PCI-E slots and low and behold the same screen flickering problem occured, my other 8800GTS didn't do this so that how i came to the conclusion that the card was bad.. Anyways, i ended going back to Fry's and returned both 8800Gt's for a GTX, now i'm back in single card mode and i'm happy once again.. Thanks for your help.😀