Is piriform.com Safe?

I installed Piriform's CCleaner on Windows XP on my Dell XPS 400. It worked fine until I added the CCleanerEnhancer. From then on, CCleaner opened every time the computer was started regardless of setting the software not to start with the computer and even removing all CCleaner and the Enhancer from the Start Folder! I finally used REVO UNINSTALL (moderate scan level) to completely uninstall both CCleaner and the Enhancer. Now with all components supposedly uninstalled and deleted from my drive. I get a pop-up every time I start the computer asking me if I want to reinstall CCleaner, and if I hit YES I am taken automatically to the Piriform website. I suspect there is some adware hidden in the CleanerEnhancer since I never had the problem until I installed the Enhancer. I, too, have found these folks to produce some great free and purchaseable software, but after this annoyance, I would not install CCleaner or Enhancer, free or not, and would would be wary of connecting to the web site and also of downloading other Piriform apps that may contain similar traps! `Withoutascent