with the scren on a laptop (HP zd7000) for the past three days.scren is black and the computer wont run but i can hook it to a tv and it runs fine.friday i uninstalled the video driver restarted the lap top and had a screen until it was shut down then saturday i uninstaled the video driver (nvidia geforce fx 5700)and reinstalled from the cd and it worked fine until we shut it down and closed the top then it wouldnt work.i tried reinstalling the video but no good,i also tried hooking it to me desk top monitor and nothing.the laptop works fine when hooked to a tv but i cant get a screen on it.could the video card be fried,if so how tough is it to change?thanks