PokerTracker

I recently installed windows 7 but when I tried to open PT3 it sayd that it couldn't connect to my database. The error message was: "Unable to login to database (template1). Reason: could not connect to server: Connection refused (0x0000274D/10061) Is the server running on host "???" and accepting TCP/IP connections on port 5432?".
Now I looked through the forums and found that starting the service would fix the problem but I don't have it in my "start"-tab anymore and I couldn't find how to start or stop the service otherwise.

Regards.

If you click Start and type Services.msc and press Enter, do you see PostgreSQL in the service list?
If it's there, can you start it?

It sounds like it either isn't installed, or you have a partial install.
In that case please make sure it is fully uninstalled (as described in the guide in the Documentation) and then install again. If you have 64-bit Windows 7 be sure to get the 64-bit version 9 from the PostgreSQL download page.