Virus Protection Business I am starting

I am starting a Virus Protection Business and looking for people that can give me some advice on marketing the product. I do not want to hire a sale rep yet, I want to work all the bugs out. My gaol is to monitor over the Internet 100 PC's by years end. I already have 20 PC's/2 companies that are using my product. Any suggestions would be great.

My thoughts:

1. News Paper Ad
2. Word of mouth
3. Chamber of Commerce