How do I reset/delete AUD.INI

That might actually work, but it's not how it's usually done. Normally, you'd want to just rename aud.ini and let SONAR create a new one when it starts up.

You will find the file in documents and settings\{your_login_name}\application data\cakewalk\sonar 8.5 producer.

Renaming it lets you go back to the original if necessary, or to compare the new one to the old one to see what changed.

In the past week, for some reason my Hopkinton installation has gone from really good to really wobbly. I've already opened a ticket regarding one problem -- suddenly I can no longer render "What You Hear" mixes of any mixes which involved aux busses (though I could still hear the signal from the aux busses on playback). Now Platinum is freezing (white screening, never responding again) or just crashing (Windows "application has stopped working" message), sometimes with a Sonar crash reporter, sometimes not, after mundane editing tasks, when saving etc.  (I'm not connected to the internet when using Sonar, by the way, so how do I send on the crash reports I've been saving -- where are they saved)?
 
It's kind of show-stopping -- even though I'm just basically comping audio, I can't seem to work more than 20 minute without a crash or terminal freeze. Sometimes I can reboot my machine and Sonar will open the last-saved file without a problem the first time I try; other times it will freeze on loading, but if I try again it will open.    
 
Anyway, I know it could be any number of things, so I'm not asking for specific remedies yet. Because -- unless someone thinks it's a bad idea -- I would first like to try deleting aud.ini, as I've seen doing so reported as the cure for many Sonar ills in many over the years.
 
But before I try this, I want to proceed with appropriate caution. Is Bitflipper's guidance, i.e.  "just rename aud.ini and let SONAR create a new one when it starts up" all there is to it? Other than, say, create a Windows restore point as an extra precaution, is there anything else I need to do? What is the worse that could happen? Couldn't I just return to where I am now (as bad as it is) by deleting the new aud.ini and changing the old, renamed aud.ini back to aud.ini?
 
I honestly have no feel for Sonar's underlying architecture etc and so just don't want to screw myself up here.  Or maybe best to wait until tech support comes back to me? 
 
I'm on a Windows 7 64 Pro SP1 laptop with a i7 2.7 Ghz CPU, 16 GB RAM, and a Focusrite Saffire 6 USB (drivers up to date). (By the way,some of the problems, like the inability to bounce mixes as described, pre-dated this week's Patch Tuesday.)  Anti-virus Is turned off when I work, disconnected form the internet with no other programmes launched. 

Thanks very much Craig. I will try it now and see what happens. 
 
Yeah, I think such bumps and buzzkills on the road to PC music making are, sadly just eternal facts of life, try as we do to avoid them, if for no other reason, than there are effectively infinite PC configurations, so inevitably, one man's safe haven can be another man's crashfest.
 
   

I did actually have this PC custom made for pro audio by Scan UK, which I'd seen recommended in the SOS forums, and with which I've generally been quite pleased. Then again, that was three years ago, and I've ... done a few things to it since then ;-)  If my troubleshooting doesn't bear fruit, other options including getting back with them, their tech people are great and accessible.

Working a few hours now, everything stable back in Mixtopia ... whew :-)