Will having two different operating systems cause problems with my internet?

It is better for you to install Windows XP in your old laptop unless the hardware specification can be achieved for Windows 7. Window 7 is the high graphics operating system, and it needs a lot of RAMs so, it is better to install it in your latest laptop. Hopefully, its hardware specification will satisfy the minimum requirement for Windows 7 installations. As far as your question is concerned, there will be no problem for running the internet if two windows operating systems are installed in your laptop. Because you only can run one operating system at a time so, there will be no problem for the internet browsing. However, the internet is faster in Windows 7 than Windows XP operating system. The performance of the internet in Windows 7 is rather faster and smoother. So, you don't have to think that the two operating systems will damage the performance of the internet. However, one thing you have to remember that you have to tweak the internet settings in Windows XP to make it faster and reliable. For this tweaking, you have to keep yourself aware of the internet protocol settings, and it will give you the maximum benefits from this approach. So, use the two Windows operating systems in your computer without any worry and make your internet browsing memorable.