How to break up large .WMV file

[twestfall]

Hi - I know little to nothing about video editing and I'm hoping someone can help me figure out how to do this. I have a .WMV file that is almost 4GB and is approximately 55 minutes long. The problem is that it is one looonnnngggg stream. You can't fastforward, go in reverse, nothing like that. Is there a way that I can change the file so that I can fastforward, jump ahead, move backwards etc...

Please keep in mind that I know NOTHING about this stuff so treat me like the newbie I am!

Thanks!