too little information to troubleshoot.
if you’re lazy, get vlc media player. it should handle most files you throw at it. http://www.videolan.org
otherwise, find out what codec the avi file uses with something like gspot, and download the appropriate codec (xvid, divx, whatever). you can also download something like ffdshow-tryouts that will include most commonly used codecs, and which will work with windows media player. http://ffdshow-tryout.sourceforge.net
I have a weird problem, in the last few days when I try to play this format movies they keep stuck and the after few seconds they are ok and again after few seconds they get stuck again. in HD form their is no problem. I have downloded Codec latest version and installed it but it Didn’t help. I am using WIN7.
Do you guys have any idea please ?