Along these lines... I can't get Firefox on my new computer to play .wmv files. The OS is Media Center (MCE) and WMP10 came preinstalled. I installed Firefox and get the missing plug-in graphic but it doesn't know which plug-in to install. I tried reinstalling WMP10 but it tells me I have a newer version already installed. I'm guessing this has to do with having MCE as I've never had an issue with straight XP.