Damm Computers!

I'm sorry if this has been asked before, and I did look through the memories and FAQ's to see if it had been asked but didn't find it.

My question is not realy about making icons, but rather my computer saving them.
Receintly my computer started saving animated icons as a bmp instead of a gif.
What the heck? I can't figure out how to change it to save them correctly, much less WHY it started doing this out of the blue.

Any help?? Ideas ??

Thank you for your help