Avoid installing any extraneous software. Also remove all the junk that came on the laptop originally. Find out the easiest way to do that here.
Of course, you don't have to go with Windows. A MacBook Pro has the hardware requirements necessary for this task. As recording computers, Macs are generally very stable and responsive. Just be sure you buy OSX-compatible recording hardware and software.
The laptop should be for music purposes only. Get it to the point where it works and leave it alone. You want to be sure it will always work when you need. Keep it off the Internet as much as possible. Don't even let it connect to a network except your own. You want viruses to stay away.