mine worked fine in 32 bit windows 7. Now that I got 64 bit, I believe I downloaded the 64 bit 7zip and I have a similar problem. the 7 zip file refuses to associate with 7 zip; it associates with an unknown file type and 7 zip is not a choice presented. I think there's another place to tell it that 7 zip is the program, but it absolutely refuses to associate. However I can right click I believe and tell it to open with 7 zip and it works. Weird.