windows 7 computer freezes after power save turns of monitor

Just put this computer together, everything is stock, no overclocking. Seems to run fine, played a few hours of modern warfare 2 with no issues.

I noticed It seems to freeze after the monitor gets turned off by the power save mode. I just set it to turn off displays after 1 minute of inactivity, waited watched the monitor turn off, then I went to the move the mouse and the screen came back on but the cursor would not move. sometimes the screen will not even come back on.

I have turned the computer on, left the room while it was booting to eat breakfast or take a shower, came back the screen was still on but the computer was frozen. Window 7 login screen was up, but there were some graphic glitches. this has happened a couple of times.

If I manually put the computer to sleep it seems to come back properly.

msi p45 platinum 1.6 bios
e5200 intel dual core
4 x 1gb ddr2 (from hp rebate deal, nanya brand)
nvidia gtx 260 (195.63 drivers x64)
win7 ultimate x64
enermax 720w powersupply