Problems installing WordPress on Demon.net server

Hello I am hoping that someone can help me.
I am trying to install WordPress on a Demon.net server but keep getting a failed to establish database connection error message.
The info that I have to provide i.e db_user and db_password are correct, I believe the problem is with the db_name and db_host variables.
I am getting conflicting info as to what these are but none of the options seem to work!

I am hoping against hope that some either knows what the specific variables needed or has successfully installed WordPress on a Demon.net server.

I have the current variables as db_name= myaccountusername
and db_host = localhost.

I keep getting through to a call centre and after literally hours of phone tooing and froing I thought I’d try a forum.

Thanks in advance!!
Hanniel
[email protected]