You can do it without buying anything, but it takes some work - You often have to take a multi-pronged approach to eradicate all the malware. One product usually doesn't do it alone. The following are general instructions, and the advice may vary depending on what type of malware you have

First download the latest versions of the following (if the virus is blocking your internet, you may have to download these on another machine and burn to CD or copy to a USB memory stick)

Malwarebytes: http://www.malwarebytes.org/mbam.php

ComboFix http://download.bleepingcomputer.com/sUB…

Download these to your desktop and before running them, change their names
Malwarebytes: mblah.scr
ComboFix: comfix.exe

Superantispyware: http://www.superantispyware.com/superant…

CCleaner (cleans out caches) http://www.ccleaner.com

Avast! 4 Home: http://www.avast.com/eng/download-avast-…

Now, start the machine in Safe Mode (hit the F8 function key as the machine boots up, and choose Safe mode)

Turn off System Restore on your machine, but only until you get this fixed - many of these trojans get copied into the System Restore files, which anti-virus programs aren't allowed to touch and the viruses could reinstall themselves from there. My Computer > Properties > System Restore.

Then run CCleaner (it'll make scanning faster because it will delete a bunch of temp files and save you from having to scan those.) If the virus blocks CCleaner from running, proceed to the next step.

Then run Malwarebytes (mblah), and clean everything it says.

Then run ComboFix (comfix), and clean everything it says. If it tells you to reboot your machine during the process, do so immediately.

Then install and run Avast - tell Avast to do a boot-scan - click on "schedule boot-scan" - and restart the computer

Let it start and do the Avast boot scan

Then turn System Restore back on.

Now install the antivirus program of your choice to do continuous scanning, and make sure you keep it up to date. Install SuperAntiSypware.

Always keep your Windows, web browser and Java software up to date - frequent patches are released to plug security holes.
http://www.pcworld.com/article/149298/10…

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