>I got this old app in 2.6 foxpro, but then some of the files are "archive-compress-whoknows" into this filename.PAK files.

Mark,

PAK indicates that the file is in compressed format. PAK predates zip.

My suggestion would be to go to a file library(www.hotfiles.com) and do a search on either PAK or compression. I am sure the PAK program is avail as shareware.