I have an occasion to work on a pc that has vertical lines across the icons on the screen. When the customer plays tripeaks, some of the cards show up black with vertical lines across them. The lines appear only after windows 98 finishes loading. They really show up across the whole monitor when you go to shut down. I have changed the monitor and moved the pci video card to a different slot with no success. Is it the video card or a corrupt windows file? Any suggestions?