I am going to reinstall OS tomorrow;best way to protect my system?

[bspkumar]

I am going to reinstall OS tomorrow after facing many problems with malware and virus issues with internet  ( Files are downloading automatically without my concern )

So, I request you to suggest steps I have to follow before installing and immediately after installing the OS .

( Best antivirus, best firewall,best adware..........etc )

You can suggest me anything to get rid of these malware issues.

[Zylstra]

You can use Windows Firewall if you are using XP SP2 or higher.

The first thing you do:
INSTALL An Antivirus program.
Either Avast (www.avast.com , my personal favorite)
Or AVG (http://free.avg.com/)
You might also grab AVG Antispyware as well

Second thing:
Run Windows Update! Set Automatic Updates up as well, your computer should at some point prompt you with an advanced Windows Update setup, make sure Updates install at a time when your computer is usually on.

Third Thing:
Your system, at this point, should be protected to a descent point.