My entire monitor flashes black for a second or so when starting any video file. It does the same thing when closing the file. It also does this when opening a folder that has video files and a thumbnail view, or when I do anything that presumably accesses the video stream inside a video file.

It happens in VLC and Windows Media Player, though it occurs to me certain video editors I have like avidemux and virtualdub don't have that issue when opening video files... It also does not happen when watching flash-based videos on web sites.

It doesn't seem to happen when Quicktime.

I went through and uninstalled any extraneous programs a week or so ago and didn't see any change.

I also updated the graphics card driver.

What can I do to troubleshoot/fix this?