Windows 7: Do I need to download an anti-malware?

hai friends,
I have Guardian Antivirus installed in my system.It also has a built-in antimalware tool.
I wanted to know that do I need to download any other antimalware software(I was thinking to download one from microsoft.com)?
If yes,which is the best which can perform all operations like antimalware,antispyware,etc?

Never run 2 antivirus/spyware software at the same time. They slow down the machine nad can interfer with each other!

What is the best antivirus/anti malware tool.....? That's very difficult to decide.

• virusses not recognized
• false positives
• memory usage
• cpu usage
• ease of use
• ease of install
• price

I should install an all-in-one solution that is a virusscanner and malware scanner.

Microsoft Security Essentials - Free Antivirus for Windows is free, simple and just works

Two programs many use with success. Yes you need protection for your computer.
1. MSE
2. MAM
Microsoft Security Essentials - Free Antivirus for Windows
http://www.malwarebytes.org/lp/malware_lp_form

I have no opinion on Guardian AV, as I don't know enough about it to do so. If you're happy with it, then that's all that matters. As for your main question, most people that are security oriented use two free products to supplement their AVs; Malwarebytes and Hitman Pro.

They are both considered to be among the very best malware scanners on the market, and I happen to agree. They are great tools in the war against malware and should be used at least once per month, or more depending on your surfing habits.

Malwarebytes : Free anti-malware download
Home - SurfRight

If you have not had any infection problems in the past then installing another Anti-Malware Program may not be of any further help.

If however you insist on having another program then Malwarebytes Anti-Malware is a very good program and has already been suggested by many.

You don't install a anti malware or anti virus program because your computer is uninfected; you install it to try and keep it that way. Another way, you don't put a roof on your house because it's raining that day. You do it because it might rain tomorrow.
Security is absolutely necessary for your computing pleasure.

If a computer is working for a long time, say over two years, without getting infected then historically I would consider the security already provided as adequate and not start installing more security applications.

Where a small firearm does the job adequately, you don't have to bring in more artillery for defense.