ComputerBB

I troubleshoot computer problems for a handful of guys in Engineering. The problem has risen from several that when they highlight and select a command from a pull down menu, the command below the highlighted selected one is activated. This happens in AutoCAD and one person said it does it in Word. We run Windows XP. Please help me so I can calm everybody down. We have only had XP in the last 6 months. Is there a bug in it. Thanks, Bob