Scared to Buy a New Laptop

It's about time for a new computer. I'm a little shy about pulling the trigger though, for one reason: my really good laptop flat out refuses to work with the wireless comcast internet. I gave it to my son because the router is in his room and he can hardline in. I am using my good, but not as good laptop to work on because it works with the wireless in the house now. I never had that problem before with my other one, although I did have plenty of problems with it and won't buy a HP again. It still works wirelessly on other systems like our portable wireless device when we go out on the boat, or at the library, just not on comcast. What's with that? Is it because it is a Vista? I've read that some Vista laptops have that problem. That would calm my nerves about buying a new laptop if I new that was the case because most new ones come with 7 now, and I'd want that anyway because the one thing I LOVE about the laptop (newer than the other one) that I'm using now is it has Windows 7 on it. That was a vast improvement over Vista. I'm just scared that I'll spend a lot of money on a really good new laptop, and have it not want to work with my wireless internet in the house.