I would say that you have installed some other player that is interfering with WMP (win media player).
Do you have any idea which is the name of this player? Go to the Add/Remove Programms in Control Panel and try to identify this program and uninstall it.
If you cannot find it or this doesn't work, you could try to install WMP again. You could try to get a newer version from windows update.
I am running WinXP. Had no problem with video trailers etc... or viewing from Win Media Player before.
Now when I want to see a video tailer the viewing area opens and in the top left corner I see a Red Box, Green Circle, and Blue Triangle there.
Also when I open Media Player a window pops up telling me of an internal error.
Any suggestions or helpful advice?