Which Free Antivirus program should I get?

[citystreet]

I just built my pc and everything has been a success!
I attempted to install McAfee VirusScan Home Edition 13 on my new PC since I got it for free from school.
Before installing a message popped up saying "This program has known compatibility issues" and at the bottom it says to check for solutions or run the program. I ignored it and ran the program anyway. After going through the steps installing the security center, virus scan, firewall, siteadvisor, and etc. a message pops up after each item has a check next to it.
The message says McAfee integrated security platform installer has stopped working. then i have to close the program. I believe this is because it is an older version of McAfee that is not supported by Windows 7.

What is a good antivirus software that I can get for free?
I heard that Avast and Avira are good, but i am not sure which one to install.
I am not too sure about Microsoft Security Essentials because that seems to be a prime target to try and hack.

Any suggestions?

 

[Ijack]

You've already discounted the best suggestion. Never mind.

 

[citystreet]

If you are talking about Micorsoft Security Essentials I am still open to hear about it and your suggestions

 

[belial2k]

AVG is the most popular of the free antivirus programs.

 

[jimmy2legs]

i wouldn't touch avg personally.... my uncle is a techie and he swears by it, so it must be decent. i prefer Avast, it's impressed me so far. i haven't had windows 7 long but it works well with it so far. and for the past 3 years i've used them.
The interface is nice and clean, and usually easy to use (except for a few skins), virus database seems to update almost every day, so if they aren't doing their job, they sure are doing a good job of making it look like it.

 

[Dark Lord of Tech]

avast 5.0

 

[esd2000]

avira anitvir

 

[esd2000]

running windows 7 with no issues

 

[jaguarskx]

I use Avast!

 

[saran008]

Avira Antivir