If not is there one that is really cheap, also once you get it is it a one time scan or does it stay on your computer and you can use it whenever you need it? What all does it takes off your computer? Does it takes off programs too or just internet files?

Ok, so my computer has been running pretty raggedy latly and i had just a bunch of junk on it. I run antivirus that updates regularly, i have spyware scans i do regularly, i do everything you can. I run zone alarm. So i just deleted a lot of things, but how can i clean memory and remove pointless things that are just acting as clutter? What else can i do other than completly formatting to help my computer.
Yes, i defrag like every 4 weeks or so. I delete everything i run scandisk everything is fine. But it jsut runs slow not like it should to my standards at least. Is there a way to clean windows or clean memory or do something to kind of refresh it? For some reason i jsut think my windows operating system is a clutter from all the stuff i download. I just think it should be performing better

you know those annoying things that say "clean up your desktop click here to learn how" or "your running out of space on disk x:" etc