Get a video conversion program, such as AVI Video Converter, to convert the file.
Not sure why you want to "compress" the file other than to send it somewhere, as various video formats compress the raw file in the process of converting it (i.e. some video formats such as .flv files are much smaller than avi files).
The two main compression programs for windows computers are Winzip and WinRar.
Answers & Comments
Get a video conversion program, such as AVI Video Converter, to convert the file.
Not sure why you want to "compress" the file other than to send it somewhere, as various video formats compress the raw file in the process of converting it (i.e. some video formats such as .flv files are much smaller than avi files).
The two main compression programs for windows computers are Winzip and WinRar.