Well, if buying a new laptop, you'll surely be getting Windows Vista; there are five versions of Windows Vista. I think Vista Home Premium would be fine for you. With Vista, be sure to get a computer with at least 1GB of memory. And, 2GB may well be worth paying a little more.
Nearly all new laptops come with built-in Wi-Fi; just be sure to confirm that before you buy. In other words, they are capable of picking Wi-Fi signals without installing/attaching any additional hardware.
Sure, Norton can be installed. A new laptop may have a trial version of Norton already installed. But, I suggest avoiding Norton and getting
AVG Anti-Virus Free or
Avast Home Edition. Norton is too much of a resource hog.
Regarding installing games, sure, you can do that. All you need is a DVD-ROM drive, which a new laptop is sure to have.
In summary, since your requirements are actually fairly basic, most laptops on the market would meet your requirements. So, you can stay in the lower end of the price spectrum if you want to keep the cost down.