At a bare MINIMUM, Windows 7 MUST have Service Pack 1 maintenance applied, due to Sonar dependencies on redistributable routines that only become part of Windows with that set of maintenance.
It is super important to have Windows 7 maintenance up to date.
Let's start with the above, and then we can dig into whatever is happening beyond that.
Please also list the details of your system's specifications, so that we know what we are working with. You can look at my signature at the bottom of this post for an idea of what to list, or someone else's.
Since there are NOT widespread reports of Sonar failing to install, it is QUITE likely that we can get this figured out and get you up and running. X3 is actually regarded as extremely stable, and one of the best releases they have ever put out, so I firmly believe this to be a solvable situation.
Once all Windows maintenance is applied, I believe another complete removal of the partial install of Sonar that had failed should be done, prior to attempting another install.
Bob Bone