Can't play AVIs

[bugsy140]

I am having trouble viewing AVIs that I have downloaded. I am not exactly a computer genius but would like to be able to view things that I download. I have no problem with MPEGS. My MPEGS are played on Windows Media Player and my operating system is windows XP if this helps. Can anyone help me?
Also I would like to somehow join my movie files together to turn short clips into one longer clip. Can this be done and if so how?

Thanks

[1 Smelly Fish]

You have double posted, check your other post

Cheers