Playing older games on widescreen monitor, how to stop screen from stretching?

Hi there,

I have been interested in playing some older games such as Diablo 2 on my PC, but I get annoyed by how the game's picture stretches out to fit my widescreen monitor. Its really annoying because it distorts the image. I want to buy some old games from Steam as well, but since older games do not have support for widescreen, it turns me off... is there a way I can stop the screen from stretching and simply add some black bars around the sides instead? have Windows Vista and nVidia graphics card. I have been trying to search for some options to do this but can't find anything... any suggestions?

Thanks in advance :)

I would either play windowed or check in the screen settings, there must be something in there to do just that.masterdrat