No I only use WMP when I have to. That's why I suggsted you keep a backup player just in case WMP has difficulties.

You can try to open it in GSpot & it will tell you what codec needs to play it: http://www.headbands.com/gspot/

Oh as far as the icons go, highlight one of these such files & go to menu File>Properties>Open with/Change & select wmp10 & choose always. That should do the trick with any luck.