Best free antivirus software

I am looking for a recommendation for the best free antivirus software out there. Not stuffed with ads or blotware.
Who is Participating?

[Product update] Infrastructure Analysis Tool is now available with Business Accounts.Learn More

I wear a lot of hats...

"The solutions and answers provided on Experts Exchange have been extremely helpful to me over the last few years. I wear a lot of hats - Developer, Database Administrator, Help Desk, etc., so I know a lot of things but not a lot about one thing. Experts Exchange gives me answers from people who do know a lot about one thing, in a easy to use platform." -Todd S.

I personally use Microsoft Security Essentials/Windows Defender.    It's free for Windows 7 and built into Window 8.    No ads or bloatware.   I've installed this for many clients and it has worked out well for them.
If you mean for personal use, then it is Panda Free Antivirus. It uses very little resources and I haven't had any problems with it yet in the many years since I've used it.

For non personal use, then only m$'s security essentials, but you are only allowed to use it on up to 10 PC's in a company. If you use more PC's, then you need a non-free product.

If it is for Linux, then clam is good, and it is included in the repositories of most major distributions.

Experts Exchange Solution brought to you by

Your issues matter to us.

Facing a tech roadblock? Get the help and guidance you need from experienced professionals who care. Ask your question anytime, anywhere, with no hassle.

Start your 7-day free trial
I second rindi. We also like Panda Free Antivirus.
Thomas Zucker-ScharffSolution GuideCommented:
That is kind of like asking what is your favorite ice cream flavor.  That being said, I would vote for MSE for few machines, AVAST! has some good qualities.  But I have to say that you generally get what you pay for.  I like Malwarebytes Antimalware Professional.
It's more than this solution.Get answers and train to solve all your tech problems - anytime, anywhere.Try it for free Edge Out The Competitionfor your dream job with proven skills and certifications.Get started today Stand Outas the employee with proven skills.Start learning today for free Move Your Career Forwardwith certification training in the latest technologies.Start your trial today

From novice to tech pro — start learning today.