I am new here so please forgive me if I sound dumb!

I have successfully downloaded a file - first hurdle passed! It ends in .XviD. If I open it through the BitComet window I can play it in both RealPlayer and Windows Media Player. I have two questions:

1. How the hell do I save it to my desktop?! As soon as I try to do this it won't open from the desktop!

2. How do I convert this file so that I can use DivX converter to burn it to a DVD that will play in my dvd player (not only on the PC).

Anyone out there who can put me out of my misery? Pleeeeeaaaaaassssseeee!!!!