Question : Task Bar Disappears When I Attempt to Launch the Command Prompt

When I try to launch the Command Prompt the Task Bar disappears and then comes back. It is almost like when Windows crashes. The Task Bar disappears and the System Tray empties. Everything comes back within about 30 seconds. I have tried to launch the Command Prompt three ways:
 1) Start | Run | cmd
 2) Programs | Accessories | Command Prompt
 3) I have created a shortcut in my Quick Launch for the Command Prompt.
The Command Prompt does not appear using any of these methods. I have been running complete Windows Defender scans as well as full Kaspersky Anti-Virus scans, but no virus or spyware has been detected. This is a Windows XP Home machine.

Answer : Task Bar Disappears When I Attempt to Launch the Command Prompt

Thanks to all who shared ideas. Unfortunately, I did not find a solution. In the end I used Acronis to restore an image from December.