Help with Media Player Classic

Anyone familiar with the inner workings of Media Player Classic?

I’ve used it for a few years and it’s great. Plays just about any kind of file with minimal fuss. The only issues I’ve had have been upon updating it or changing over to a new computer and figuring out my settings again. That’s what happened this time.

On my previous computer pressing the “P” key would toggle through different screen settings, I believe cycling through different aspect ratios. This was really helpful to get a movie letterboxed, or a TV show un-letterboxed. On my newest machine (running XP and the latest version of MPC), the P key does nothing. I found the area in “options” to change key assignments, but I can’t seem to find a way to assign the function I want.

I can’t find anything about this in their support materials or by Googling. Any help?