PC Screen Suddenly Locks but the mouse is Still Moveable

Hello!
I reloaded my PC 3 days ago just to clear up unnecessary files and what not. My PC is a year old. My problem began last night. My computer screen suddenly locks and nothing is clickable nor am I able to hover over it. The mouse pointer is the only movable thing on the screen. It seems to happen at random. I am at a lost of what to do. I am desperate to resolve this problem.

Thank you
- Mobster

Hello Mobster mate can you boot into safe mode? If so try running these

http://www.sevenforums.com/tutorials/1538-sfc-scannow-command-system-file-checker.html

http://www.sevenforums.com/tutorials/433-disk-check.html < use the /f option in Option 2 ifnecessary

A little update on my problem. The freeze happenes every 30 minutes on the nose. Its like clockwork. Some icons are able to be highlighted and clicked. But when they are clicked, they dont do a thing but load and never load up. I asked numerous people, including my computer manufacturer, but to no avail. My warranty ran out around a week ago so Acer was no help. Im really stumped here.

As post #2 Mobster can you get into safe mode and run those scans?