I try to edit some videos but every time i edit them the audio is ruined. it sounds like cut off the audio every now and then. The file it self doesn't have the ruined audio.
Unfortunately you have given us very little information so any advice is bound to be so general as to be almost useless.
First, please read this post and give us ALL the information requested there. We don't know anything about your computer, the version of Windows you have nor even the variant of MEP 14 you're using and how you are editing your video files. (Which "view" are you using in MEP?)
Also, tell us exactly what you mean when you say the "audio is ruined"; perhaps post a short sample of this ruined audio to Dropbox or similar file-sharing site and post a link to it in any reply. That way we fellow-users can download and listen to it and perhaps gain a much better idea of what you are hearing.