Re: Upgrading from Feisty to Natty?
Yes, it is possible to upgrade from Feisty to Natty, but not directly. It would be a long process as you would have to upgrade to each of the releases along the way, i.e., 7.04 to 7.10 to 8.04 to 8.10 etc. You might be able to bypass some by going from a LTS to the next LTS in the process.
I do not recommend going this route.
Are you sure your old computer is capable of running Natty? Does the live CD work with the "try" option?
Ubuntu 13.04 64-bit on HP dv7-1267cl, 3GB RAM, ATI HD3200