so i got a laptop a few months ago and i've bee using that at college instead of my pc. I turned of my pc so it wouldn't just be running for a while for no reason. i turned it on a week or 2 ago and there is just no picture. ive narrowed it down to my video card which is 2 years od, 7800 gt. i used that little digital to analog converter thing but i used the same one and plugged it into my laptop and works great. i've taken the video card out, cleaned the dust out, cleaned the inside of my computer. what should i do?