Display choppy/hanging at random times

My display seems to freeze up for 1-3 seconds at random times. It hangs up during videos, while typing, pretty much whenever something is happening on the screen. It seems to be completely random, as Youtube videos freeze up just as often as it does while typing these words. It won't even keep up with the text when typing a .txt document in notepad.

Toshiba P755-S5215 Laptop
Windows 7 Home Premium 64 bit
i3 2.1 GHz CPU
6 GB factory installed RAM

I recently did a system restore for other reasons. It was acting up before, but is worse now. All drivers are up to date. Windows update did everything it needed to. I checked the Task Manager, and no suspicious processes or services are running. Disk is not fragmented. Memory diagnostic said the computer's memory is fine.

I am out of ideas of things to check. I would appreciate any help I can get.

Thank you in advance for your help.
-Worlock51