I'm new to Linux. I'm using Ubuntu 11.04. Now i want to install Ubuntu 12.04 .

I got an ISO image of Ubuntu 12.04 Desktop. I put this image in to a pen drive which is formated,set the boot option boot from usb but nothing happened .

I searched this over the net and on Ubuntu website but nobody has given the complete steps . someone say u can install from the Ubuntu also ,someone says u can do a fresh installation from usb pen drive u need to make you pen drive bootable etc. etc. .

My problem is that i don't know the exact steps how ton install Ubuntu from usb pen drive?

All I want to do is to completely remove my Ubuntu 11.04 and install Ubuntu 12.04 from usb pen-drive.

Can any body tell me how to make a pen drive bootable ?

How to install Ubuntu 12.04 from pen-drive?

Please give me a step by step procedure.

please explain me how to do it step by step .

Thanx in advance