How do you change a file TO dat?? help its in the name of r4 cheats!!!!

i accidentally made the cheat files open with a program and now they are not .DAT how do i change them back??? help!!!THANK YOU!!!!!

Just rename it.
You know, right click and choose rename...P.S. The word "i" should be capitalised. (Just getting revenge for Renji217)

It still don't work... and lol about spelling thing :)

Um..change the files extensions by right clicking the file?And rename that..works for me.

How do you mean when I click on properties is says File type: video CD movie!