This isn't really too useful a tip but it helped me. While downloading an AVI file, look in your shared folder. Right click on the file and select "Open With". Browse for AVI Preview and select that as the default viewer for that file. This will make your life easier if you download many things at once (as I do) and you can see sizes and a lot of other stuff to distinguish one file from another in an explorer window rather than an "open file" one. Of course, now all .dat files will be opened by AVI Preview but, how many of us open non p2p Dat files anyway . I'm not sure if AVI Preview works for other p2p program's dat files but normally you can preview them from inside the program.