Yes you can and it depends on the phone and what OS you are looking for. Want to run Android? Sure, here is some advise for the N810 http://www.wired.com/gadgetlab/2010/08/nokia-phones-android/ and here is a great site that tells you how to [http://europe.nokia.com/support/download-software/device-software-update/faq|update for Nokia] I could be more specific if I would know which phone you are thinking about installing your OS. Nokia PC Suite is available [http://www.nokiausa.com/get-support-and-software/software/nokia-pc-suites/compatibility-and-download|here] Good Luck to you and hope this helps and just like iCris said, BACKUP YOUR STUFF :-)