I have a hp pavillion 6623 pc, having trouble getting it to start up in normal mode , it will start fine in safe mode . When try in normal it gets to the point where the desktop is loading but the screen is a a ton of lines just rolling . A few weeks ago I installed a nivida geforce 4 video card , and it worked fine ,but now for some reasonit switched back to the old video setting . I can't change it back to the geforce in safe mode .