"... to stabilize system, speed up start up ..." and so on.

The software is Uniblue Registry Booster. It comes recommended by the producer of a piece of email software that I like and use daily "Mailwasher". I believe that Mailwasher was recommended by someone here a few years ago.

My question: is it likely that this program will improve the performance, stability etc of my machine?

They offer a free scan, which showed 486 errors, 15 were fixed for free. It is $29.95 to register and continue with the clean up.

I have been having some minor problems: Outlook no longer invokes Word at the email editor unless Word is already running, minor shut downs of programs, etc.

Advice welcomed from those who know this application or its genre ...

Thanks in advance!