is there a tool to open .adi files on Mac?

I have some files on a hard drive that were archived on a Windows PC using MS backup utility. I don't currently have a Windows PC.

There are a bunch of .adi files - is there a tool (preferably free!?) available that will allow me to open those on a Mac? The files I backed up are mostly Excel, Word, etc, that I should have no trouble reading if I can get them out of the .adi archive?

Thanks!

Mark