Gnutella Forums - Laptop Virus

I need to ask a question about harmful computer viruses. I have a laptop notebook which does not have a place to protect me if i got a virus but will kick me off any site that does have one. A friend told me i had one the other day in FB, he also gave a link to protect me. I click it and it show me in colors which sites were not safe. I have check out a few things to discover these different colors from green being safe to red being a possible virus was only view by people being on those sites. How do i know for sure i am safe other then my laptop kicking me off? Please help.