How do I delete/completely uninstall Security Antivirus without needing to pay or register for something?

click start, control panel. go to programs and features,( or if your runnign an older version of windows click add/remove programs) select the program you wish to remove and click uninstall/change. follow the onscreen instructions.

You can try doing a couple of different things, they are both free:
1. Try Housecall at Trendmicro website http://housecall.trendmicro.com/
2. Download Threatfire http://www.threatfire.com/ by PC Tools. It is similar to Malwarebytes http://www.malwarebytes.org/ but will run in background while you surf the net.

I use Housecall occasionally, but use Threatfire and Malwarebytes above on a regular basis to keep my computer clean. I also use the free antivirus program Avast http://www.avast.com/free-antivirus-download. You could also use another free antivirus called AVG http://free.avg.com/us-en/homepage.

Good Luck

Hi
You don’t have to pay if you remove Security Antivirus rogue antispyware manually, i.e. delete each of its files and registry keys from your system.
Here is a guide http://windowsprotection.net/how-to-remove-security-antivirus-securityantivirus-removal-guide/ .
Give it a try

I’m having the exact same problem, but don’t download anything else…

Your computer is already in dangered.

And the manually is very complicated to understand. O.o But if I find another way to do it, i’ll edit. O.o

Don’t pay for it because Security Antivirus is a real infection. Scan with a reputable anti-spyware or read this article to make sure that I am telling the truth:
http://www.2-spyware.com/remove-security-antivirus.html
To get rid of Security Antivirus, first of all start safe mode before scanning. Then, stop its processes and then run a full system scan.