Windows 7 Aero Peek won't work

[yoshirocks]

I just noticed that when I put my cursor over a thumbnail, I get a little bar that says the name of the program instead of the Aero peek preview. I made sure Aero Peek was enabled. What's wrong?

 

[yoshirocks]

Never mind. It just fixed itself.

 

[yoshirocks]

It's not working again! It seems to be turning on and off by itself.