Video file size problem

Okay, so I was going to start my youtube channel today, but I've run into a bit of a problem. I have a half hour long hd let's play video I made, it's a .wmv file, and the file size is a little under 5gb. I tried to upload it to youtube, and it was going nowhere pretty fast. So what's the best way I can reduce the file size of my videos for uploading to youtube without taking away from the quality?

Windows Movie maker will be the easiest, though most inflexible method of converting that video.

Handbrake will be the most flexible, but will likely require further research on your part to get the full benefit.

Both are free tools.