How about telling us what software you are trying to install rather than keeping it a deep dark secret? Often knowing the software provides the answer. Usually its installation instructions provide adequate guidance.
The *.naf file might just be a compressed file and if so WinRar will open it.
I?m trying to install a music software on my pc (that doesn?t have internet connection). So first I got an ?AuthorizationRequest? file that I copied on a CD then put it on a internet-connected computer (also xp) then got a ?AuthorizationReturn.naf? file. Then I?m supposed to save it on a CD and bring it back to my music computer to complete the activation process. But when I do that, I get a message asking me with what software should Windows XP open that .naf file? ???
Any advice would be greatly appreciated