I have just bought a desktop computer system ? I have installed 2 operating systems , one is Windows xp professional and Windows 7 is the other. I had a very bad experience in my old system. My old desktop system was hit with a fatal virus and spy ware attack. I had an Anti Virus installed already but it did not detect even a single virus and I thought that my system is Virus free but later on the virus began to replicate and showed it's ill effects . I do not mind to pay for these Anti virus but cannot rely on these free Anti viruses any more. So please give your suggestions.