I bought a 2nd GTX 670 and put it into my rig for SLI. To do this I had to take out my sound card because I didn't think it would fit. It worked fine for the day I had them in SLI. After I put the sound card in with the graphics cards there were issues. When I tried to start up my system there were issues. It went to MOBO screen, starting windows, then black screen to all my 3 monitors. I could here that it loaded up windows but was black screen and couldn't do anything. Also when my computer would actually work it would randomly black screen all my 3 monitors then come back and say graphics driver has stopped responding and has recovered. I am going to try to re-install GFX drivers when I get home. And sometimes the computer will start up with black screen because of when I changed the graphics adapter in the BIOS to onboard to see whether that would fix the problem, which it did, even though I changed the main back to PCI express. I know that is the cause because when I plug my DVI into the motherboard it will work. I took out the sound card, still issues, took out second card, was fine for about a day then problems again. I really don't know what to do. Please help.