wellygary:

onetapu: I feel the problem is with Word on the old computer.

All other computers in the office are able to access Word files from the main computer no problem.

Although:

When I open Explorer on the old computer and try to access a Word file on the main computer, I get the message: "can not find the file ... or one of its components.  Make sure the file and filename are correct and that all required libraries are available".

Which would indicate there is something wrong with the filesharing, though remember I cannot open Word on the old computer.

When I uninstalled and reinstalled Word on the old computer, do all the registry bits not sort themselves out??

Is Word required to run your Old DOS program?,

if not take it off the computer and only run the programs you have to, 

You may have a bunch of corrupted registry entries, which could be a real PITA to fix, given how old the system is (most of the tools will unlikely work o such an old OS, and I certainly would be very careful about running any modern fixit tools on such an old system