I have Windows 7(64 bit) installed on my system along with Ubuntu 12.04. I want to upgrade to 14.04 version of ubuntu but since I do not have a good internet connection I am unable to upgrade it using update manager. I somehow managed to get a .iso file downloaded. Is there some way i can upgrade using a cd or usb drive? I am not sure which boot loader i have. I installed 12.04 using wubi installer. I dont want to mess up my system so please someone help me regarding this??