most distributed emulators will be in standard ZIP or RAR archive formats.
[usually in zip]
if he's running XP he shouldn't have problems opening the zip
otherwise, if the archives are in RAR. or 7z then he should really get Winrar or 7zip
it's a standard computing need
most exe's shouldn't ask for "open with's" since if it doesn't run, you'll simply get an error.
can you please tell us what you're trying to do?
what's the file extension of the file you're trying to open?
Cheers and Goodluck
-Leerz