Can we install OS in our mobile phones ourselves

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/n... and here is a great site that tells you how to 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 here Good Luck to you and hope this helps and just like iCris said, BACKUP YOUR STUFF :-)

how to instal the my mobile os

"yes we can do it by installing nokia recovery tool

That helps to recover our data and also to install any nokia phone os easily

USE IT it will be helpful for microsoft and nokia users"