No I havent had anti Virus for about 3 years now but I cant open any internet browsers without them being in Admin mode now :|
I remember making a VM open, all ports no firewall antivirus; Within 1hour it had been attacked about 1000 times.
I stopped using antivirus since 2010. Until now i have been attacked about 1-2 times. I remember one of the virus was ghey pr0n image file on my desktop that couldnt have been deleted. The other virus was probably created by a dumb kid. It was a keylogger. All i did was terminating one svchost fake process and deleting 2 files. I am still not using antivirus. I will recommend u downloading AVG. Good luck solving ur issue. Another advice is simply reinstalling ur OS. Make sure that the problem isnt caused by some of the windows's settings for administrator rights and stuff.
I re-installed everytime my PC was slow cuz I was thinking of a virus, which is about...3 re-installs per week a few years ago.