After I installed two gtx 660 ti's and turned my comp on, it turned off immediately. I tried to turn it back on again but It wouldn't do so. I took out the new one I added and tried with my regular set up. This time it worked, except I smelt something weird from my computer around the cpu/psu area. Could've been a burning smell but I can't be certain I immediately shut my system off and took a look at the cpu first. Was fine except there wasn't that much thermal paste from my last application, So I reapplied some and put it back together and tried again (only 1 gpu). It worked fine and no smell. However, when I play games, it runs at 700 mhz instead of its usual 950 mhz (no overclock). I believe I couldn't run SLI because my psu couldn't handle two cards, but could the psu make my card burn in my case?
i5 3570 (non k)
asus gtx 660 ti
asus p8z77 lk
ocz 700w 80 plus (non bronze, silver or gold)
A bad PSU can kill parts if it doesn't distribute voltage correctly, and OCZ isn't exactly a stellar company in general.
I would stay away from EVGA power supplies as well. Go with a company that is known for making power supplies like Seasonic, Corsair, Silverstone, Enermax, Lepa, NZXT, or XFX.
Keep in mind that the power supply might not be the problem either. I've had SLI issues before because of a bad motherboard, but if the system isn't turning on at all with both cards in, then I would think it would be the power supply.
I would go with one of these if I were you:
NZXT Hale82N 750 watt - http://www.amazon.com/dp/B008RK9V46/?tag=pcpapi-20
Corsair TX750 - http://us.ncix.com/products/?usaffiliateid=1000031504&sku=58382&vpn=CP-9020042-NA&manufacture=Corsair&promoid=1258
Corsair HX750 - http://www.newegg.com/Product/Product.aspx?Item=N82E16817139010&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=3938566&SID=