Windows Media Player 11 Running Slow On Vista

Hi my Windows Media Player 11 is Running Slow On Vista
it use to be fine but then one day i formted i hard drive and decided to start again now i've noticed no matter what sort of video file i run though wmp 11 it runs slow thats avi mpg divx xvid even dvd's i've tryed installing codec's but that's not worked before i formated my hard drve the only codec's i had on there is the ones i have now which is divx xvid and ac3 filter which use to running everything fine but now everything keeps runnnin slow and it is really starting to bug me

sorry if this is in the wrong place not sure where to post it

any thoughts on this problem guys and girls

thanks for your time in advance