Screen keeps flashing in photoshop

[Dstoll]

I need some help!! For the longest time (months and months) my photoshop has done this flashing thing on and off and I can't get it to stop! It's frustrating! Anytime I scroll or use a tool it flashes.  sometimes even if I'm not doing anything it flashes, how do I get it to stop?? Any help greatly appreciated 

[Damien Symonds]

Let's try this first.

Also, do this for me.

[Dstoll]

Thank you so much it worked!

[Dstoll]

I have a PC laptop running Windows 8 and Photoshop Cs6. It is under 2 years old, and has 4GB of RAM. Its hard drive has 2GB free out of 4GB. The last time I shut down was earlier today. I run a cleanup program about once a month.

[Samantha LaRue]

That can't be right. I don't think your harddrive is only 4gb, with 2gb free. Can you check that part again?