i wont to change os in my nokia E5 n i can't find any os other than symbian n i have heard alot about firefox os so i wish to install it can i do so?
It is not possible to install FirefoxOS on a Nokia E5 device. The Nokia E5 device runs a Symbian operating system and Firefox is not supported on Symbian OS. FirefoxOS is supported on Android devices and the list of devices supporting FirefoxOS is listed here https://developer.mozilla.org/en-US/Firefox_OS/Firefox_OS_build_prerequisites
Hope this helps