I'm experimenting between two computers, which one runs SONAR HomeStudio6 the best.
But I only have one copy of the program.
Can I only have one copy running on one machine at any given time, or can I have two versions on two machines, as long as only one machine is ON at a time?

You can put the program on 2 different computers as long as you're only using 1 at a time.

Thanks.

Is there a limit to how many times SONAR can be installed/uninstalled/re-installed?

I don't think so, but eventually, OS changes will force a change in which program you use.

wrong.note.rod


Thanks.

Is there a limit to how many times SONAR can be installed/uninstalled/re-installed?

Greg's right. There is no dictated limit.  You own the license forever.
However, there may be a practical limit. As Greg noted, changes in OS may eventually render your version of Sonar obsolete.
On a more immediate note, repeated install/uninstall cycles is probably a bad idea. It can leave trash in the registry that may cause more harm than good. 
In general, most problems on the initial install have to do with settings or system/hardware issues, and a re-install is not warranted.
Are you having problems on either machine?
If so, give us some specifics. Maybe we can help.

Also, you can't sell it.