The key to remember when looking at security is just because it is a big brand and expensive doesnt mean it is good.
Virus, AVG free download scanner, Trend micor free online scan and other's provide just as good and better performance in most cases than a paid for version.
One of the best places i have found for information and utilities for pc's is
www.download.com
All programs are free of adware and spyware, site also have user reviews and rating and contains a large number of freeware and shareware prodcuts. Well worth a vist before paying for products.