When i put a video in movie maker or any my video converters the video quality turns terrible! Help?

When I put a video in movie maker and click on the play button (in movie maker) the quality becomes terrible. This also happens when i put a video in one of my video converters and click convert.The output (converted file ) turns into terrible quality. I have chosen all the right setting in my software but this... show more When I put a video in movie maker and click on the play button (in movie maker) the quality becomes terrible. This also happens when i put a video in one of my video converters and click convert.The output (converted file ) turns into terrible quality. I have chosen all the right setting in my software but this still happens.Please help ! Any working answer will IMMEDIATELY BE REWARDED points !
Update: When I put a video in movie maker and click on the play button (in movie maker) the quality becomes terrible. This also happens when i put a video in one of my video converters and click convert.The output (converted file ) turns into terrible quality. I have chosen all the right setting in my software but this... show more When I put a video in movie maker and click on the play button (in movie maker) the quality becomes terrible. This also happens when i put a video in one of my video converters and click convert.The output (converted file ) turns into terrible quality. I have chosen all the right setting in my software but this still happens.Please help ! And yes i have chosen the right output file .....one with good sound and video quality.Any working answer will IMMEDIATELY BE REWARDED points !

Note-Only after the movie gets into movie maker and i click play the quality turns terrible!
Update 2: Another important note !-My converter and movie maker used to work fine before only now it has started turning the video to bad quality. please help!
Update 3: Im using Iwisoft video converter!
10 answers 10