AVG free on my desk top which is win7 64bit; but on my laptop I have to run Bullguard because AVG stops the desktop Icons working! that is also win7 64bit.
I had another older laptop which had been converted to win 7 had trouble with AVG on that after the conversion.
Got fed-up and got the new laptop had the same problem; thus the Bullguard software.
Weird or what!
I have this on one machine and I must say it is excellent.
I have BitDefender on another and will not be renewing the licence when it expires. While there is nothing in particular wrong with how it works, it has a tendancy to give a false report of "invalid licence" every now and again on boot up and I need to reboot my computer to get AV protection running. I will most likely replace it with MS Security Essentials.
On the third machine Kaspersky Internet Secuirty which is fine and was a lot cheaper than Nortons. When the licence expires it too will most likely be replaced with MS Security Essentials.
I have used Nortons for many years and while I find it good value for money as a new install, the licence renewal costs are too high.