Desktop sides and top, cut off

Hello,
I powered on my Win 7 (32 bit) computer today and noticed that the top and sides of my display were black (2" top and sides). When the desktop appeared, the icons on the left along with the Windows Orb were also cut off ... as if I had "taped over" the sides and top of the monitor!? Also the "Notification Area" was not visible in the lower right hand corner. When I opened the start menu the left side of the menu is also "taped over", so I can not see any of the programs there.

I did a "hard reset" (press and hold the power button) and once again the same "taped over" effect.

Another hard reset and restarted in Safemode. I could now see all of my desktop icons including the top of the display. I did a Restart and once again, "taped over".

Restart > Safemode > System Restore > again "taped over" display.

Restart > Normal > "taped over" display at Login screen

Logged in > Display back to normal???

This happened once before about three months ago. Can't remember what I did then to fix it.

Thanks for any help.

Samsung 20" Monitor
Nividia GeForce 9200 Display Adapter
RAM: 3 GB
Processor: AMD Athlon Dual Core 2.10 Ghz