Computer security questions, desktop.

[Metal Man 2]

I am looking at getting a new desktop system(windows 7) set up and running this weekend. BUT I do not have any security set up for it. I have been using a laptop (windows XP) for a couple years that I run
Mal-ware
CC Cleaner
Webroot anti-virus with spy sweeper (can I switch this from the laptop to the desktop or will I have to pay again?)

I dont think they are the best since I still have had problems with virus's.

I also want to figure out how to put a pass word on all down loads and filter out bad sites. Any help would be appreciated.

This computer will be for "business" only. I have a couple kids also that will be using the computer and need to be sure they dont download unnecessary stuff. I need for this computer to run clean and trouble free.

Thanks for any help, opinions or links if you can.

 

[jamesd1981]

avg and microsoft security essentials are good anti-virus, malwarebytes and iobit security 360 are good malware/spyware cleaners, ccleaner and iobit toolbox are good system cleaners, and they are all free no time limit