I have been seeing some software slowdowns over the past month or so, and am going to wipe the disk clean and reinstall the operating system. It has been a while since I have undertaken such a job, and I have a few admittedly minor questions. How long will this take? I have the original OSX disks that came with the machine, will I need software serial numbers or anything along those lines? If yes, where do I find those? I have both time machine and external backups, will I be able to say, restore the contents of mailboxes from time machine, (with attachments), and leave everything else alone, (using copies of my documents and iTunes libraries from an external drive...)? Is this a common thing? Thanks for the help!