For some odd reason, cats seem to like sprawling across a computer keyboard, especially on laptop computers. While it may look cute to have a cat near a computer, be careful with cat hair. Cat hair can clog up the fans of a computer, overheating the machine as a result.
Also be aware of putting your computer on the floor where cat hair can more readily clog the fans. You can put filters over the fans but a regular cleaning should be considered general maintenance to make sure your computer remains working, despite anything your cat might do.