AVI and MP4 problems

[luvmeeh]

Hello I just installed this wonderful program to solve a problem I have been having with my MKV files on this Vista for 3 years now and it is a heaven send but it won't play AVi and MP4 properly. The pictures are comming out fne but no sound I tried everything but it won't work I would love to keep this program but I might have to go back to my old Pack for the AVI problem. Please help!!!!