Of all the so-called downloadable PC Doc-Registry Fix-yada-yada out there, do any actually deliver the goods?

It's mind boggling how many of these people claim to, after a "free scam" opps!... I meant free scan claim to have the program that'll heal everything thats wrong with your PC....for anywhere from $19.99 up to a 7 day access number lease for only "the amazingly low cost of $39.99". Do any of these sites actually do what they want you to believe? and if so, which one have you found gives you the most bang for your buck? I've been drawn into their net before and after having dished out $24.95 and having had between 250 and 300 errors repaired, I was curious so I had a "free scam" ...(opps, I did it again),...at a different site. They appearantly found 742 more that the other place must have not caught....very odd indeed considering this is a pretty new comp... What gives. Are any of these places legit. It's a bummer that you can't really purchase anything on the internet without somewhere down deep asking yourself "are they or aren't they??"