Possible Duplicate:
Is it possible to “upgrade” from a 32bit to a 64bit installation?
I updated 11.10 (32 bit) to 12.04 via update manager, but the OS is still 32 bit but not default 64 bit. I would like to install 64 bit 12.04 ubuntu. How can do it? by the way is it possible for the coexistence of 32 bit Win and 64 bit Ubuntu?
Thank you in advance.
Jinxiang
