> I have a simple app, which needs to run for a few users, written in C#.net. The users to not have the ability to run an install on their own computers, so we must install via a simple xcopy.

If the user must not install software it is not an good practise to
install it by xcopy.

Ask the people forbidding software installation for an exception.

> Currently we are using SQLite, but the performance is pretty bad when the db gets a bit large.

The speed problem might be caused by placing database on shared drive.
Forcing firebird to do the same might run into the same problem.

> Can I have a Firebird db file on a shared drive, and have multiple (two or three) users accessing it using the embedded edition of Firebird? I have read the existing similar posts and am still not clear if this situation is supported.

This is definitely not supported

> I cannot install a server, I cannot run a Windows install on the users' computers.

You can run the server without installation by just starting fbserver.exe.

Perhaps it is an solution to run the server on one of the users machine.
The problem is that database will be available only while this user is
logged in.

Elmar



Elmar