Here's the thing. IF Sonar itself was at fault for the issues you are having, then there would be an ENDLESS set of very loudly typed complaints about it - in other words, we would easily see a whole bunch of threads/posts indicating some major problems with the current release of Sonar.
The fact that this is NOT the case, indicates a high probability that the issues you are currently experiencing, as maddening as they most certainly are, are likely to be some set of solvable local issues with your system, like maintenance or interference from other programs, or some sort of download issues (perhaps antivirus corruption of downloaded files), or that sort of thing.
The GOOD thing is that because whatever is going on for you is likely some sort of local system issue, it is also QUITE probable that with your engagement in the debugging analysis, and the assistance of a bunch of really helpful and knowledgeable forum folks, we can get to the bottom of the issues and get your system fixed up.
To DO that, we really need more information ABOUT your system, and details about the issues you are having. We really do need to know what OS you are running, whether or not you are up to date with Windows maintenance, etc., as had been asked in a post above - prior to this one.
In addition, it really is a good idea that you go through an uninstall of all of the demo software, since you won't be using it anyways, and because it will help eliminate things that for whatever reason might interfere with the proper installation and operation of both Sonar and the Cakewalk Command Center.
So, please provide:
Operating system, and indication on its maintenance condition
Cakewalk Command Center version
Sound card or audio interface being used, AND information on version of its drivers
Computer info: CPU, memory, hard drive models (it makes a difference)
Any detail you can provide about installation of Sonar, including demo versions, etc.
There are a bunch of folks here that will bend over backwards to help you get all of this sorted out, and I hope you are willing to work with us to get you squared away. :)
Bob Bone