Vista - Taskbar Flashing and Blurry Madness

I am a serious gamer and I sometimes play games for long periods. This has
happened to me many times and what happens is when I play a game (doesn't
matter which one) for 3 hours or more or leave the game running for some
time, the taskbar *flashes* but not only that but it shows the taskbar above
at the top of the screen when it is always at the bottom. Then when I finish
the game I cannot open any window not even my computer because the window
looks blurry so I can't see anything. I can't even use the start bar because
that is all blurred out also. So the only way I can play the game again is
too reboot or go ctrl-alt-delete and select the I/O button and then I select
restart.
I am running 32-bit version of Vista Home Premium with a 2.8 GHz Pentium 4
and 1024MB Ram, using a Geforce 7600GT.
--
Processor: 4.0
Memory: (RAM) 4.2
Graphics: 5.9
Gaming Graphics: 5.4
Primary Hard Disc: 5.8