> I have system using FB1.5 which has worked well since before FB1.5
> came out.
>
> Recently, the server on which it runs was changed to a virtual
> machine and another application (not mine) running on FB2.X was also
> installed. I now have a situation where I get multiple instances of
> the FB1.5 fbserver.exe appear several times a day. When that
> happens, FB does not allow anyone to log on.
>[...]
> Does anyone know (or can speculate) what might be instantiating extra
> copies of fbserver.exe?

To be honest, I can't quite imaging what you mean by "extra copies" or
"multiple instances" of fbserver.exe.

But maybe I can help you anyway: It is perfectly possible to run
multiple Firebird servers, even in different versions, on the same
machine. It is happening right now at the computer I am using. The
process of accomplishing it is described in
{FIREBIRD}\doc\install_windows_manually.txt.

Pepak