Вірезка из доки по FB1.5. Лично я делаю батничек с fbserver.exe -a и ставлю его в автозагрузку и на рабочий стол - всё отлично работает.

2.1. Required steps

If you don't have a special setup program (it's distributed
separately) the steps are the following:

- unzip the archive into the separate directory (since a few
file names were changed, it doesn't make sense to unzip
v1.5 files into the directory with IB/FB1)
- change the current directory to <root>\bin (here and below
<root> is the directory where v1.5 files are located)
- run instreg.exe:
instreg.exe install <root>
it causes the installation path to be written into the registry
(HKLM\Software\Firebird\FirebirdSQL\CurrentVersion)
- if you want to register a service, run also instsvc.exe:
instsvc.exe install <root>
- optionally, you should copy both fbclient.dll and gds32.dll
to the OS system directory

2.2. Installation of CS

To install the CS engine, the only difference is the additional
option for instsvc.exe:
instsvc.exe install <root> -classic

It means that you may have only one copy of the engine (either
fbserver.exe or fb_inet_server.exe) to be installed as a service.

2.3. Simplified setup

If you don't need a registered service, then you may avoid running
both instreg.exe and instsvc.exe. In this case you should just unzip
the archive into a separate directory and run the server:
fbserver.exe -a
It should treat its parent directory as a root directory in this
case.

2.4. Uninstallation

To remove FB 1.5 you should:

- stop the server
- run "instreg.exe remove"
- run "instsvc.exe remove"
- delete installation directory
- delete fbclient.dll and gds32.dll from the OS system directory