Gary, >From what I've read and experienced, it appears OS 8.6 is the best mix between performance and compatibility. I suppose it depends on what you're trying to do with the machine, but I think wireless and cardbus for USB would be available in 8.6. I know 8.6 has fewer cardbus issues than the 9 series. However, I'm not the most experienced 2400c user here, so I'll defer to wiser judgment. Morris On 10/9/05, Gary F. Daught <gfdaught at charter.net> wrote: > Greetings. The PowerBook 2400c I am getting is currently configured > with 2GB hard drive, 80MB RAM, and running System 7.6. I amy > eventually opt for a larger hard drive, but will likely live with the > existing 80MB RAM. I am thinking about an OS upgrade and would be > interested in your advice regarding the best OS to run under this > configuration. Oh, I am definitely interested in getting a wireless > pc card, and may eventually get a USB pc card (if the 2400 is truly > CardBus compliant). Thoughts?