Depending upon your OS, just having the likes of adaware, av software, etc. will not be enough. And, from what I've experienced through the years (been working with computers for over 20 years now), just having one av program, one anti-ad program is also insufficient. I've used as many as 4 different av programs just to get one virus removed from someone's PC or MAC, and in dealing with adware, I've used as many as 5 and 6 to remove all the troublesome files. I've since settled upon 3 antispyware programs and 2 av utilities to keep things safe. My suggestion is that you tryout the programs yourself and make your own decision as to what will work best for you.
Plus, depending upon your OS and your internet connection, you need to make certain that you have some sort of firewall protection. With dialup, it's not that much of an issue--but with cable and DSL it is. Windows and Mac both have firewall protection built-in; with the Mac being safer considering that there are 5 open ports on the PC right out of the box. You'll need to familiarize yourself with the firewall settings on your computer (go to the library and check out a good book on your OS if you don't have any information that came with your computer related to setting up your firewall). If you have a business, or if you have cable or DSL, you might also want to consider getting some firewall hardware and or software in addition since the standard firewall protection with Windows isn't sufficient. The most important thing is to close those ports.
Lastly, you could always switch to Unix or a Mac, much safer than PC's--even though I own only PC's running windows myself at the moment. In the future, I'll have a Mac or two and a PC running Unix to keep things safer.
Have a great day!