Since I continue to have sluggish behavior from Platinum that I have not been able to track down, I am considering re-installing to see if it might help. My question is.... will I lose all my personal settings and basically just be starting over from scratch?

No, Sonar install looks at prior installs and uses those preferences. 
 
But I'm not sure re installing is always the answer. It's usually your computes set up that would cause your issue. 

Cactus Music: About the only things I haven't tried are re-installing Sonar and re-installing Windows. Sonar used to be very responsive but, maybe six months ago, it has gotten really sluggish. It doesn't stop me from using it, I've just learned to just give every move a second or two to actually happen but, it is really annoying. Not at all what I had always been accustomed to. I have a 5 year old i5 with 8 Gb RAM. Focusrite Saffire Pro 40 and Octopre. Maybe Sonar has just become too much for my system to handle? I'm just trying out anything I can think of to try. So far, nothing has made any difference.

Deleted - Duplicate Post

Deleted - Duplicate Post

Deleted - Duplicate Post

My Sonar has slowed as well. I'm going upgrade my entire system. Not entirely because of Sonar being slow, I'm just WAY overdue for an upgrade.
I do agree with the other post that I would suspect the system, before Sonar.
If you haven't already, update all drivers. Even ones you don't think have anything to do with the issue.
Try to remember what you might have installed since you installed Sonar. Things like that stupid Chromium malware from Google Chrome. Things like that sneak in and rob the PC's focus from your work.
Good luck!

You can't remove a post but just choose edit and delete the content and leave a  "edited, duplicate post" 
 
Have you run Latency Monitor to track down issues..
And for me if the internet connection is on it will slow things down even if I'm not browsing. I have to disable my Network connection, I also run a 4 year old i5 so , ya things could be faster but as long as I optimize and stay off line all is good. 
 
Another thing I did was installed a fresh SSD drive just for Sonar Projects and that has also perked things up. Projects open in a flash and exports seems faster now too. 

Latency Mon shows nothing of concern. Have tried with the internet on and off and it was the same either way. All drivers, to the best of my knowledge, have been updated. I do not use Google Chrome. Sonar used to run really fast, now everything is sluggish with an approximate one to two second delay. 
Interestingly, it appears that the actions of the program itself are working pretty instantaneously, it seems to be the graphics that are behind. I say this because, when I do a punch in it starts actually recording right on cue but, visually, the screen shows the spinning blue thing for 1 or 2 seconds before it starts moving. 

Do you have on board video or a dedicated card, Possibly a inexpensive video card might take the load off?