Windows 7 Antivirus 2012 popup.

I was watching youtube and suddenly got a pop up about windows 7 antivirus 2012, and I know its fake so I immediately ended the IE process via task manager. I was wondering if my computer has been infected or not because I have read other threads that it installs itself, but my computer doesn't seem to have it installed and is running normally. I have also scanned wit avast and malwarebytes and came up empty.

Should I be worried about a virus infection?

Strange that avast didn't do anthing about it.

Welcome to Sevenforums, by the way!

Update both it and malwarebytes and do a full scan on both, one after the other. Then go running, or have a hearty breakfast, etc. (it may be a while).

Then go into "manage add-ons" in IE and make sure you only have add-ons you need, such as shockwave player. disable any other ones that you don't. I've seen many "coupon" add-ons in the past and truth is they aren't needed and often pose a security risk.

*Important!:warn: Make sure all important windows updates are installed, as many of them are security fixes!

You might also consider installing many of the optional windows updates that have to do with IE, and if you don't already, IE9 is more secure than IE8 and worth the upgrade!

This virus has been around long enough Avast should of picked it up. Of course if the OP was keeping Avast updated.
Using Task Manger was a good move.
You can use any anti virus; I have chose MSE. along with MAM Pro.

I should also have mentioned that you should uninstall any IE add-ons that you have, and reintall them from their website (so that they are updated and it fixes any potential issues in the program's files).

For example, flash player can be installed from get.adobe.com/flash

Let us know if you need any further help or if it comes back.