I may not have Windows at home, but I have to agree with my 3 colleagues here, aviationgypsy.
32 bit systems are completely losing support. I have software at work that is 64 bit compatible only.
Now regarding the antiviruses. In simple terminology, 2 or more antiviruses create congestion in a computer. Your computer will slow down, whether you like it or not. Not to mention that they will bother each other.
By the way, I've seen how 1 antivirus thinks that the other is a virus, and vice versa. (It ain't pretty)