It's been a while since I did an upgrade for gaming, but I used to be up on all the latest. I took a break, bought MW3 and now I need a hand with a new gpu. I have a 5 year old or so pc with an amd 9500 quad core. Unfortunately I don't know the model of my motherboard offhand. It has an nvidia 8500GT in it now which doesn't run MW3. I got an XFX 6750 HD. Installed it, and realized my psu didn't have the new 6pin plug. So, I just finished installing a new PSU (corsair gaming series 700watt) with the 6 pin plug. Installed new card.... no video. I put the old card back in, and everything is working fine. Is there a newer pci express standard? I think my motherboard has the original pciexpress slots. Thanks in advance for any help and/or info.