Media player won't work

Hi Guys. I had problems as regards playing any type of film; my computer just wouldn’t do it. Not even VLC or SM player. So, I downloaded Vista codec package. VLC and SM will now play films, however Media player won’t, any ideas????? Thanx..

windows 7 32 bit, gigabyte s-series P35T-DS3P, Intel Core2Duo, 2GB Corsair DDR3 RAM, 500GB seagate sata, Nvidia GeForce 11.0