Laptop computer. Side view of the keyboard (left) and screen (right) of a laptop computer. The screen and keyboard are joined together by a hinge to make the computer an all in one foldable unit. Laptop computers are portable and can be used anywhere, powered either by batteries or by a connection to mains electricity. With the correct hardware, laptop computers can be linked to other computers and phone connections to access electronic mail (e-mail) and the Internet.