Getting pop up about malicious url blocked

This morning i opened firefox and it started popping up (attachment) http://plugin.we-care.com/UpdatePlugin.php?tday blocked. it happens a lot on facebook. i did a malwarebytes scan and nothing. i did the tdsskiller thing and there was nothing. now when i open firefox it pops up and when i open facebook this pops up http://lb.we-care.com/appContent/facebook.com?height as blocked. i havent installed anything in the last few days so i dont know whats going on. i keep my pc clean and run malwarebytes daily and avast full scan weekly.

Try this first and let me know if it continues

Download AdwCleaner from here to your desktop
Run AdwCleaner and select Delete

https://dl.dropbox.com/u/73555776/AdwCleaner.GIF

Once done it will ask to reboot, allow this
On reboot a log will be produced please attach that