Like I said, That 500w was meant for a test run, to prove what is at fault, GPU or PSU. For that purpose, it worked just fine.
He bought another Fortron 700w, which is more than adequate (18A on 4 separate 12v rails). It claims to have more than 90% efficiency if particular load balance is achieved. Not sure I believe that, but ok.
And rather impressive 6 year warranty.
But since stock 8800gtx shouldn't take more than about 12A, than even that borrowed 500w should do just fine in long term too.