Verified answer

Avast is the best you can get for free.

http://www.avast.com/en-us/index

ESET is better, but you pay for it.

You want a 30 day free trial, go ahead, but then get Avast.

2

If you are going to keep any free anti-virus stay with Avira. I like it because is good and is not disturbing me in any way. The trial Nod32 it will be for a short time and after you will have to pay or to return to a free one.

Avira Free/

Works for me.

It is better to use AVG 2011, best detection rates Android stops viruses Android spyware from getting to your pc.

If you want one of the best secutity programs out there I suggest using Norton internet Security (latest edition).

Both are good, but if you use Antivir (which I use) configure it like follows

This is to setup antivir after it has been installed.

Right click on the logo in the taskbar(a red square with a white umbrella), then left click configure. Towards the top left, you will see a box beside expert mode. Check this box. Now click the + beside scanner, and now the + beside scan. This will expand them.

Now click on scan itself to where it is highlighted. Now to the right under files, select the circle beside all files. Now click on action for concerning files. To the right, click the circle beside automatic. Now to the right of that, set primary action to repair and secondary action to delete. Check the box that says "copy file to quarantine before action".

Now click on archives to where it is highlighted. Make sure all boxes on this page are checked, if not check them. Now click on heuristic. To the right under win32 file heuristic, check the box beside "win32 file heurisitic", then click the circle beside medium detection level.

Now click the + beside guard and the + beside scan to expand them. Now click on scan to where it is highlighted. To the right under scan mode, check "scan when reading and writing". To the right of that under files, click the circle beside "all files".

Now click on heuristic to where it is highlighted. Check the box beside win32 file heuristic, and then click the circle beside medium detection level. Now click ok and antivir is now setup for scanning

Also, my personal opinion from years of working on computers, Norton Antivirus is the worst.

NEITHER!

For FULL protection, see links below

none. go for avast or AVG