I would back it up to be able to rebuild it exactly as it was delivered to me. Then I'd remove the preloaded apps that I don't want and then I would perform the upgrade to Ultimate. If you have to create a set of restoration CDs or DVD, you should do it first.
You are about to answer a thread that has been inactive for more than 6 months. If you still wish to proceed, please ensure that your posting is original and does not duplicate or overlap any prior responses to this thread.