My CCD needs a parallel port so when my old laptops hinges smashed I had great difficulty getting a lappy with a parallel port. I think the same thing applies now with serial port. I got one second hand from
http://www.laptop.com.au/
You don't need as powerful computer to run a camera or a guider. I don't process anything on mine, just transfer the files via a thumb drive onto my desktop. If the computer is just to go outside in the dew with your scope get a cheap one that is essentially disposable.