I have a Gainward GF4 Ti4600 that has never been O/C yet. Well about a week after putting it in I started to get strange vertical lines on my screen and lots of character shifting and blinking...sometimes the problem goes away but it always comes back....If I push on the card or jiggle it while the computer is on...somethimes is clears....do you think it could be a seating issue or is it a bad card?