" Once done, I rebooted and found it finished booting then crashed. "
As we move from computer owners that could wield sharp knives and perform a high wire act at the same time, this sounds interesting but if this crashed a good system, it tells me that I can't advise this one.
Along the similar lines of CCleaner, this has proven to be a helpful pgm.. To this user, it appears to be more aggressive in cleaning tasks. It also has tools to remove apps/pgms. and runs across win9x-win8 OSes, so it seems worthwhile.
Caveat: Upon initial 1st use, don't proceed until you created a new restore point. As i did use the freeware version, I did some cleaning. It found more than CCleaner would have, check link for reasons. On my Win7x64 well over 3k of files needed to be removed. Now, I did a very limited check of that file list, but found re-appeared temp and cache files even after using CCleaner. I ran the SN w/o any setting changes using the "Junk Scanner", as is installed. After sometime, I allowed it to delete the listing of files. Once done, I rebooted and found it finished booting then crashed. I did a "repair" of the system and it did whatever it needed and I didn't select restore option just allow it to finish the repair. *** It would be at this time, an user could then select the restore process and go back prior to SN use.*** I didn't and once the repair completed, I rebooted it found nothing wrong this time and it works. No nagging or glitches afterwords, it just works.
Caveat: I do suggest its use but not when you have a serious problem. It's more a house keeping pgm. IMHO.