Windows 7: Aero Preview not working properly

Hello Seven Forums!
I have a problem with the Aero Preview feature. With programs like Mozilla Firefox and VLC Media Player, Aero Preview does this:

This is real and I have no clue how to fix it. I tried troubleshooting but it found a bunch of other problems I don't even have. If you don't get what's wrong, it only shows part of the window and it's really annoying and restoring and minimizing don't help.

Thanks.

start with SFC /SCANNOW Command - System File Checker. restart upon finding violations.

Are you running any third party theme or window modifiers?

No I am not I keep the vanilla look because I like my PC fast, but preety at the same time. It might be Triple-Core but custom and third-party themes slow it down. I have never put any of those programs in my computer.




P.S.: My computer is 4 months old

I think I found the problem! VLC Media Player does it. In twitter, someone had posted a video that played with the VLC Plugin. Then this started happening to the window. I closed it and now it's OK. I reopened that video and it happened again. Does that help? I guess I will post a thread in VideoLan troubleshooting... If someone knows how to fix this thing with VLC please say so.

Which version of VLC do you have? I found the latest 2.x upgrades to be too intrusive and buggy. I reverted.

You're right! I updated last week or so... It's been buggy since then... I have to revert...