I have connected to about a dozen Windows 7 residential computers where there has been more damage done by the software (mentioned in the title) than good. Bottom line folks, Windows 7 is self-sufficient.
To speed-up your system, disable AERO (Classic Theme) then go into Advanced Settings in System Properties and disable all the animations for Explorer Windows. Do just those couple of simple things and your system will become much faster.
Then type msconfig
into your search field in the Start Menu and un-check everything that does not pertain to Security or Wireless software. Tada! You're system is just about optimized.
Next, download a really good Defragger like Auslogic or Smart Defrag. You get a great GUI so you can watch the process and those two are far superior to the built in Defragger in Windows 7 and Vista.
Honestly, Windows 7 does not need the other utilities. Simply un-install all the crapware, any peer-to-peer software (inherently dangerous) and remove all toolbars. You're good to go.
Backup! Install a fresh installation, get all Windows Updates, all Security Updates, remove all crapware that came with your computer (as mentioned above) and then create a backup on DVDs, an External HDD or Internal HDD. Never delete or discard that pristine backup--it will come in handy someday.
Backup! All your game, music, video etc., files to DVD, your second HDD or a USB Drive. If your system crashes----your good to go in a fraction of the time of doing a complete factory recovery.
Lastly, come here for Reg Files and manual instructions on advanced tweaks to your system. I'm very good at what I do on a daily basis with computers around the world---but if it's an advanced tweak that I have not worked with yet, I find everything I need right here at SevenForums.com . So will you!