bfg 8600 gts o.c. quit working what should i do to test it before sending in for warranty replacement?

My wife played Sims 3 all day when she saved and quit at 9pm yesterday the video card quit sending information to the monitor. I rebooted the computer manually with no sucess. I then turned off the power to the computer and left it alone for five minutes came back and rebooted to no sucess. I did note that the cards fan was running. I shut down the computer again removed the card and hooked up the onboard video with the old vga cable. The monitor worked fine. What at home tests should I do now before sending the card in for a replacement?