Thanks for the suggestions. I actually suspected the virus software and/or firewall in the very beginning but the situation doesn't seem to improve without them. I did check the Dell website and found that there are no updates for the video driver.

I have noticed an anomaly that started about the same time ISE was installed. Whenever I use a popup menu, it leaves a ghost of the menu bar on the monitor for a second or two. This never happened before. I've been tempted to blame this on McAfee...