PC-Plus was the name of the character-based (MS-DOS) accounting solution for SOHO (small office/home office) market that was released by PC&C ApS in 1984, three years before the release of the first version of Navision.
A small Danish VAR bought the rights to the PCPlus program before Microsoft acquired Navision, so they were able to continue to support and sell the system, as it not longer worked on new version of Windows. And until a few years ago it has been possible to buy this system, who still today have a lot of users in Denmark. There was even stories that they got a lot of new customers when Microsoft decided to stop support the Concorde C4 application, to get the users to move to the newer Dynamics C5 application.