I have two computers, a Vista and an XP, on my XP everything works perfectly, there's a sound button in the convo window and the skins work fine and when I type /sound [soundname] it plays like usual. On my XP however, no skins work (correct version, restarted and everything) and whenever I type /sound [soundname] it just sends the function itself and doesn't play anything, I also cannot hear sounds from my contacts.

I have WLM 2009 and the newest version of M!P installed on both computers, what's the problem?

I already uninstalled the conflicting programs but still I see no result, I even reinstalled M!P.