GamingX

Hi, I installed Windows 7 Basic initially thinking Home Premium or Ultimate will be too much for the hardware I have, but since then I did a few upgrades on the hardware and think that my PC should be able to support Ultimate. But the problem is, I have no idea how to upgrade. I tried inserting the Windows 7 Disc but get some kind of error about the DVD being older than the current version of Windows 7. As for the online upgrade, I don't have that internet speeds that would be required to go for it. Is it possible to use the Windows 7 Disc to boot up and then install on the same partition of the Windows Basic without having to format it ? Or are there any other alternatives ?