I doubt you will find anything that actually works that you dont either need to pay money for or at least sign up for.
That one I linked to is still free you just need to put in an email address.
If it's such a huge hassle them having your email either make another email acount with something like hotmail or gmail or use a disposable email address like http://10minutemail.com/10MinuteMail/index.html to sign up and get the keycode.
Exactly. You have to understand as well that registration doesnt mean a program isnt free, all it means is they want an email address from you.
Mainly because they will probably want to send you an offer every now and then to buy one of their other products if you like their free ones.
That's why I suggested using a disposable email, because that way you get your free cleanup program and dont get any of their email newsletters.
Your other option is to pirate some of the paid software, but I wouldnt recommend doing that with software that is meant to clean and secure your PC.