i could be rong but it almost certainly sounds like a codec problem. try uninstalling ur codecs again and install nemo codec pack which u can get here:
http://nimo.titanesk.com/modules/fre...index.php?id=1
if u dont know much about codecs u should use the lite pack. if anything goes rong or it doesnt help just uninstall it and if anyone else cant help u might think about uninstalling sp2.