First off, if it is a retail DVD, or one that is copyrighted or encrypted, you shouldn't be doing that anyway!
But if it's your own DVD video, I'm sure this can be done.
You need to do 2 things:
1) "Rip" the DVD into standard files on your hard drive.
2) Convert those files into a single WMV.
Here are some tools you can look in to:
DVDShrink:
Freeware, can copy the DVD to your hard drive.
http://www.dvdshrink.org/what.html
Windows movie maker, may be able to import these files, not sure.
Also Microsoft Media Encoder may be able to help:
http://www.microsoft.com/downloads/...02-e496-465a-bba9-b2f1182cdf24&DisplayLang=en
Otherwise, just search google for a program to convert the files created by DVDShrink, into WMV.
Good luck!