Thanks for the replies. I downloaded and installed 7-zip, but thus far can't get it to do what I want.
An example of what I wish to do is a set of 33 Rar parts, that automatically -- when I highlighted the r0 part and asked it to extract -- extracted the rared files to a folder with 33 Zip files in it. Using WinZip any one of those Zip files unpacks to a folder with three files: another rar file, numbered r0 in the first one, an nfo file and a file id.diz. If I manually unpack the zip files, clicking on yes to all when each part unpacks to a new copy of the nfo file amd the file id.diz, I get a new set of rar files plus one copy of the nfo and the file id.diz. At that point I can highlight the r0 file and extract here to get the final unpacked file. I can and have done this manual operation with files of up to 60 parts -- tedious but it works.
Tomorrow I will try again to see if I can figure out any way to do with 7-zip what I have been doing manually.
The best software I have found thus far was ExtractNow which will extract each of the zip files into a folder containg all three of the files I mentioned above. I can then move the 33 rar files to a folder to do the extract, but that is almost as bad as the manual operation.
Again, thanks for the help. I hope 7-zip can do what I wish to do, but haven't been able to do it thus far.