Vista - decoding

i have a lot of movies that i have recordered to my DVR that i now want to
record to my hard drive and burn to dvd. So far i have not had a prob till i
started to record this one movie ...when i go into Movie Maker and import it
all i get is a black screen in my Movie Maker window. When i go into my Media
Center and look in my recorded from TV folder it tells me that the movie is
copy protected...that tells me that this movie needs to be decoded. However
this is strange to me because all of the other movies that i have copied off
my DVR to my computer have copied and burned with no prob..

My OS is Vista Home Premiun and i thought that it came with a decoder ...but
i may be wrong about that ...can anyone help me to fix this prob so that it
wont happen again with other movies.

Thanks for the help

Patti