Hi,
 
For some reason all of a sudden sonar just hangs when I try to open a project.  I'm running professional on AMD dual core with 12 megs ram.  Where should I start?  Nothing has changed recently on the computer.  The projects do contain MACHFIVE 3.  I'm thinking maybe it's hanging on trying to open that.  I did a search of the forums on sudden mysterious  crashes, but didn't find much.  

So now it wont even open.  I've already reinstalled it once.  

This troubkeshooting issue should be moved into Sonar forums.
Run Sonar in safe mode.
If you are running Reflecktor roll back a version.

Nevermind, It was MOTU MACHFIVE 3.  Last time I use that sampler.  So even though I eliminated all tracks with MOTU in it, sonar still asks (upon opening in safe mode) whether I want to load MOTU.  This is the problem basically.  How do I tell it to TOTALLY forget all references to that program, so that it doesn't try to load it?

Deleting tracks does not remove the synth from the project. Open the synth tab in the media browser and delete the synth from the synth rack.

thank you very much.

In the Plugin Manager you can select it in the centre column and select Exclude plugin. Or you can choose to install it but you probably want to use it standalone.