AVG has worked fine for me, I use the free version of the anti-virus and anti-spyware ... they also have a free anti-rootkit available. I also leave windows defender running, which is free from microsoft.com.
With all those and other programs running at startup, I have no latency issues with a AMD 3500+ processor and 1 GB @ 200 MHz RAM.
There is a free program called force delete. If the pc claims the file is in use elsewhere, there is also a freeware called unlocker. It will free up the file to be able to be removed. I believe both of them (if not all things mentioned) are available from cnet download.
Between all the freeware programs I have found, it has gotten rid of any problems I have ever had.
I also recommend firefox with ad block plus and no script to protect you while surfing.
I haven't tried the other programs mentioned, but I also don't have money to be spending on yearly software charges.
I am not the moral police, so I could care less if you were looking up porn or ponies ... hopefully not both together though
Just be careful of the files you open up from mail, most AV and AS programs allow you to scan before opening with a right click option and are active scanners. Having a mail account with a place like yahoo, they scan files before they are attached and before you receive them. The browser with the two extensions I mentioned protects you while you surf, and you can set certain sites, like -oscarfishlover.com- to be permanently allowed, or temporarily allow other sites like petsmart.com