Q:
A: Yes, it is better to remove one Anti-virus before installing another. Avast is a good anti-virus http://www.avast.com/eng/download-avast-home.html [Free home edition] Avira is also a good anti-virus http://www.free-av.com Windows Defender is recommended in addition for real-time spy-ware protection. http://www.microsoft.com/windows/products/winfamily/defender/default.mspx Remember to only have one anti-virus installed on your PC