Dave, is it only WMP that's giving you trouble? Any error messages? I kept getting: "Windows Media Player has stopped working!" Duh! I already knew that.

My solution was to download MediaMonkey (qv) and I haven't looked back. MM is free and has several kewl features that I've never discovered in WMP including a very effective volume leveling algorithm that will level an entire folder.

There is a paid version but the free version does everything that I need.