in the last few days most avi files ive downloaded freeze around 1 minute and 13 seconds in, this is both using the preview feature in emule and with a finished file

(all files i had before this started play fine though)
ive never experienced this problem before and havent installed any new software recently so dont know what might be causing this
any help would be greatly appreciated
(this is while using VLC/MPC player and K-Lite Mega Codec Pack in case that helps)