Please give me your favorite PC "clean up/registry clean/ect" site…….and your favorite Anti-Virus Protection.

And WHY/REASON for your choice????

Thank you:-)
Oh yeah…please only list FREE ones if possible:-)
Thanks for all your answers so far everybody:-)

I scan with both AVG & Malware and they both say they have cleaned,healed and moved to virus vault this infection but it keeps coming back. It has disabled my MIscrosoft security center for any updates and its seems to be in the registry. ANY HELP WOULD BE GREATLY APPREICATED–GOING BONKERS!!!!!

How to fix windows registry?

What are some good freeware to clean and fix windows registry? Also, what are some good anti-virus available? Help please!