You can go to a website called SNAPFILES. You will find a tab called Freeware. Find the Virus program called Avast. Very good program. I have been using it for a couple of years and have had no issues keeping my computer virus free.
You can remove the infection from your machine using some tools
process explorer : help u to find out the process running on your machine, check the location of unwanted process , stop that process, and remove the infected file from the locations.
Hijack this- shows everything that load when system starts, run a scan and check the unwanted files and click on fix ( be careful while doing this)
this will remove the infection manually, however you need a good antivirus software which stop your machine from being infected, the best available in market are kaspersky, mcafee.
Once you’re infected, you can never really trust your machine, even if antivirus/anti-malware programs are able to “clean” the junk off. Best bet is to backup your personal files and use your computer’s restore utility to take it back to factory settings. That procedure will wipe out any infection and restore a clean image to your computer. See my latest post: https://itknowledgeexchange.techtarget.com/security-corner/infected-pc/
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The only way to remove the virus infection of your computer system is to use your Norton antivirus to scan the entire system. However, you said that it is outdated. You have to update it or purchase the latest version of norton internet security to remove those threats.