Redownloaded and reinstalled GoG a couple of times I still get this error while trying to start it.

Title of the error is "GalaxyClient.exe - the point of entry was not found

"The entry point QueryWorkingSetEX of the process was not found in the dynamic connection library PSAPI.DLL"

This is only a rough translation. I was able to install GoG galaxy in the past"

The computer which im trying to install it on is an HP mini netbook.

What OS are you using?
You need Win 7 or higher these days to install Galaxy.

Oh yes, I forgot. WinXP SP3. I assume there isn't a roll back version.

Unfortunately not. There is a user made patch floating about the forum that might help, I'll try get the link for it later.

The XP patch did work for me. However I have shifted to Windows 7 for several weeks, so I have no idea if it still work.
https://www.gog.com/forum/general/gog_galaxy_for_windows_xpvista_patch

Yes, the patch worked!

Thanks a bunch.