I see you posted in the Spyware Forum before and Grif pitched in. I hope that in the future you ask about those cleaners in advance there. Almost all the moderators will dis these things.
Grif and rest all have some ideas. You'd be surprised that most of us have read your post before under many other names.
While trying to solve a Windows XP repair issue, I came across PC Cleaner, which purports to do stuff like that. I downloaded the trial version and ran it, and found a fairly routine registry scan/temp file delete/startup organizer, but it promised the 'full' version' could do much more, so I went for it and spent my 30 bucks. Used Paypal, got a transaction acknowledgement, and an e-mail saying I had to call a 1-800 number to be 'activated'.
Scam, Part 1:This put me in touch with a nice chap in Pakistan (?) who said I had to set up a remote console session so he could activate my application. Still not sufficiently wary, I did so and he proceed to install and run an 'activate' program. Now, he said, I was ready to go, but first, he wanted to show me all the crap and problems that had accumulated in my Windows system. And he spent about ten minutes rambling around in my system and showing me stuff. When he opened the windows startup and claimed that all those inactivated startup apps were still dragging my system down, and then opened another events file that showed a whole bunch of services were 'stopped', I started to become suspicious. I said it was a good thing I had PC Cleaner, which would fix all that. At this point he said that actually PC Cleaner won't do that, but their online support service, for $200 or more per year would, and if I signed up now, I could get the first year for $100. Then I realized I had been had, and closed the conversation. I hope I removed the 'activate' exec, which is likely a trojan, and hopefully deleted the PC Cleaner application (called 'pcleaners' in my Programs folder ).
Scam, Part 2: I reveiwed my e-mails, and found that when I had used Paypal, the transaction came not from the PC Cleaner organization, but was actually charged through an outfit called 'Safecart Payments', and that by using them I had been automatically enrolled in a service which would automatically bill me up to the full price of the software every time they released an update. I could of course, unsubscribe to this 'service' by signing onto their website. Except to do this I had to set up an account, and guess what? none of my inputs were recognized, not e-mail address, not transaction number, etc. So I could not identify that I did not want this service. Their website shows no contact number, but does have a ominous helpful FAQ: "Why haven't you responded to my request?" so I guess they are used to this. So I am closing my Paypal account to hopefully prevent further annoyance.
Bottom line - stay clear of this scam. Not only do they wave a piece of crapware to get you into a sales pitch, but they launder your supposed Paypal transaction though an intermediary who adds some services you never expected..