CCleaner is a freeware system optimization and privacy tool. It removes unused files from your system - allowing Windows to run faster and freeing up valuable hard disk space. It also cleans traces of your online activities such as your Internet history. But the best part is that it's fast and contains NO Spyware or Adware!
I've used this for since its earliest versions and faced no issues. It also helps to delete the entries that start-up the programs, whenever you start your computer.
2. http://www.maxthon.com/ Maxthon Internet Browser software is a powerful tabbed browser with a highly customizable interface. It is based on the Internet Explorer browser engine which means that what works in the IE browser will work the same in Maxthon tabbed browser but with many additional efficient features.
What i like most: Tabbed browsing, Ad (Advt) cleaning & pop-up blocker. You'll experience faster browsing, with a dial-up, as it blocks many advertisements. Make sure the red 'NO' button at the staus bar (like No Entry Sign) is clicked / pressed down.
3. Microsoft AntiSpyware. Unfortunately You can no longer download this software, which was replaced by Windows Defender (Defender is inferior to AntiSpyware)http://www.microsoft.com/athome/security/spyware/software/about/overview.mspx . I believe the threat of spyware is worse than that of virus. A good article on spyware is at http://en.wikipedia.org/wiki/Spyware
Windows defender is available at http://www.microsoft.com/athome/security/spyware/software/default.mspx
4. Anti-Virus: I had the anti-virus from CA for a few years, and its subscription ended more than 8 months ago. Unwilling to pay another $30 for renewal, I started to was search for free-for-personal-use anti-virus, and i found Avira AntiVir. Available at http://www.free-av.com/ It's quite a good product and has bagged some awards.