Major problems with Aero Peek and No Screensaver

I upgraded from Vista to Win 7 Pro, everything was working fine until a few days ago. The Aero Peek flashes for a second then goes away. Also the screen saver doesn't kick in or sleep or hibernate. I did a repair install and then a complete install also uninstalled the video card driver and and put it back on, but still nothing. I did notice when I have the device manager screen open that peek will work with everything that is open. The only thing that was changed to the laptop is that I hooked it up to a TV through the VGA. Also I deleted the old files from Vista that were stored in C:\windows\old. Haven't touched the register.

Anything that I hoover over that should show a display of some sort (such as picture, that will show the date taken, and size) it will only show for a second then disappear.

Also did a sfc\scannow which showed no problems.

System Manufacturer/Model Number Dell, Vostro 1000
OS Windows 7 Pro, 32-bit
CPU Mobile AMD Sempron Processor 3600+, 2.0GHz
Memory 2gigs
Graphics Card ATI Radeon Xpress Series 128mb
Sound Card High Definition Audio Device
Screen Resolution 1280x800

Mouse Microsoft USB Wireless Mouse (IntelliPoint)

Try swapping out that Intellipoint wireless mouse for awhile.

The memory is just enough but Sempron is a bit weak.

Stress test your memory overnight with memtest86.

You check WIndows Updates for drivers, change out any installer drivers?