I'm trying to help a friend of a friend hook an older computer up to a TV so they can display a powerpoint of upcoming events/specials in a bar. I figured the easiest way would just be to use a VGA cable and an audio cable from the computer to the TV since the computer is older and doesn't have an HDMI port. I dropped off the VGA cable yesterday but the person wasn't around so I left it with the bartender. Today, I get an email that when she hooks up the TV to her newer laptop, the picture displays fine but when she hooks it up to the older computer, it says "no signal detected". What can I check for to ensure the computer displays correctly on the TV?