windows 7 won't respond after turning screen on

I have been running windows seven for a month or two now. recently I've noticed a quark. I normally run my computer 24/7 so i set it to turn the screen off after 20 min. sometimes but not alway after i turn the screen back on and move the mouse i get an image and the mouse moves but nothing will respond for up to 90 sec. after that everything works fine. i place the mouse over an icon and when i see the icon light up i can start using my computer. at first i thought that maybe it's stopping my HDD so i went into power setting and switched to performance and then manually went in and set HDD of time to zero (never) no change

running
asus m2n32 delux mobo
amd athlon x2 5200
2 gig of gskill memory
nvidia gtx 260
2 1T HDD

any thoughts or comments would be greatly appreciated. this prob isn't detrimental just very annoying.

 

i tried hitting the power button just like you said no change the system was non responsive for over 3 min. i also tried hitting ctrl alt delete. when i did the the mouse froze. the system sat frozen for another min or so and then everything went back to normal. just like you said i turned off save power junk on two network ports and two usb root hubs.

prob a dumb question but i have my power button set to "do nothing" would that effect the test you had me run?

 

I believe the test Halo was having you run is to determine if the computer is set to enter sleep mode after a specified period of time. This is set in the power options.

 

I tested my computer this morning and still doing the same thing. It sat non responsive for over two min and then everything was fine. I also checked the sleep setting in power management and it's set to never. Any thoughts?