A Brain is needed for this one.

[Wayne]

If you don't find a ".005" in the associations list, it may be a "Hidden Association" where someone has double-clicked a .005 file and when it didn't know what program to load it with, it prompted for one, and once the program is chosen, if the #####box "Always open with this program" is #####ed, it will permanently associate with that file... The problem is, this sort of association usually doesn't appear in the list. You can ignore the association (WinRAR will still span the files through the .005 with no problem), or you can do a forced association with WinRAR by holding your SHIFT ### down while right-clicking the file. Choose "OPEN WITH", and find WinRAR in the list.

Frankly, since WinRAR will still work on the .005 even though it's associated with another program, I wouldn't worry about it if you can't find it in the list that MadForIt mentioned above.