how to convert mpeg2 to mpeg1

When I use moviemaker to string together differnt clips, it won’t import a couple of the clips that I have. Also, WMP 10 won’t play them or preview them. I downloaded a free mpeg2 player and I can now watch the clips, but still cannot import them.

Can you convert mpeg 2 to mpeg 1, assuming they are mpeg 2, and would it be worth it?

try alive video converter, please
http://www.alivemedia.net/videoconverter.htm