Yes checked all of that - in fact checked everything then decided to Uninstall and reinstall, as it may had something to do with being 2 instances. (I noticed that the upgrade was called MSSQL.2).
Anyway - now have reinstalled and its called MSSQL.3 ??
ANd I still cant get my ODBC to connect.
The ODBC on the PC 'sees' the server and shared files. It also 'sees' the sql server as the Server name is shown in the drop down list of sqlservers (Although only as the name of the Server - not the instance).
The user name and Pword of the PC logon is also set up on the server as an Admin user / pw.
Getting very frustrated now as it did work in the first place
Aha, I think I've realised what the issue is here. Your laptop does not have access.
Just because the administrator account on each machine has the same password, doesn't mean they are the same account. I suggest as a very quick test you try and access the server on the laptop using the username "sa" with a blank password.
If this works then it is a security issue you are facing. You will need to create a new login(s) with the appropriate permissions on your new SQL instance to allow the account(s) access. Check BoL on further information on how to do this.
Last up you will want to lock up the "sa" account and throw away. Seriously. Set the password using the SSMS properties window for the account and by bashing the keyboard blindly for a moment or six. You can then also disable the account in the same window.