I have been using Panda for quite a few years now, but of late once I upgraded to Windows 8 and purchased Panda Antivirus Pro 2013, its been trouble all along.
I am facing issues browsing the internet with Panda installed, it either does not allow connections via a browser or my connection speed drops to less that 200 kbps when actually I have an 8 mbps internet connection, but once I un-install the anti virus my internet works and I am able to browse at regular speeds.
Have been raising ticket after tickets but to no avail, zero response from the support team.My suggestion is not to go for this AV if you are running Windows 8, they are not there yet I guess.