I have a Dell laptop running Windows 7, with a remote 19 inch display. Last evening while on my laptop, the screen started flashing and the icons began appearing on the laptop rather than the remote display. Both the remote and the laptops displays were flashing at about a 3 second interval. I did a hard shutdown and that seemed to solve the problem. A few minutes ago I got back on and the same problem occurred. I ran the Disk Cleanup, the CCleaner, and did a Quick Scan with our Norton anti-virus. It didn't make a difference and no viruses were found. So, I did another hard shutdown and let the computer rest about 30 seconds and when I fired it up, only the laptop display showed the icons. I went to the Control Panel and the Display feature and corrected the settings so that only the remote display is used. Now, things seem to be working normally.
Any suggestions on what my problem might be? FYI, there was an automatic Windows update on 8/16.