After you know what you want to do with your new laptop computer, you have to find the software that will let you do it. This in turn will tell you what hardware you need.
If you plan on getting a laptop as an extension of your desktop computer, you'll most likely be running the same software on the laptop as on your desktop. In that case, your laptop's hardware requirements are identical to the desktop system. Bingo! You're done.
If your laptop adventure is new, what you probably need is a basic laptop setup. You want to browse the Internet, plus you want a basic Office suite of applications. That's pretty much what a typical laptop user needs.
You might also be running specific software on your laptop. If so, find out what kind of hardware that software requires. For example, if the software needs 256MB of RAM, you have to be sure that your laptop comes with at least that much RAM. If the software needs special graphics power, make a note of it. Ditto for hard drive storage, a CD-ROM, microprocessor power, and other hardware requirements.
Hardware requirements for all software packages are listed right on the side of the software box. Sometimes it's brief, and sometimes it's detailed, but it's the information you need to help you configure your new computer.
You have to refer to the software license agreement to see whether you're allowed to install a single program on both your desktop and laptop computers. Most of the time, this is considered okay by the developer because it's assumed that you won't be using both computers at one time. But some software developers, specifically Microsoft, don’t allow multiple installations from the same set of software.