Sorry if this is in the wrong spot, but I thought you would be the people who would know the answer the best. I have a Dell laptop with 32bit Vista Biz installed. I have a Dell 32bit Vista Ultimate disc and would like to upgrade so as not to have to reinstall everything else and restore personal files. When I boot up the disc, the upgrade option is not available. Is this normal for an OEM CD, and if so is there a way to make a new disc with a modification to allow for the upgrade? Or is it possible that because I have SP2 installed, the SP1 disc won't allow the upgrade because of that? Thanks in advance!

Im not really to sure but you could try removing pid.txt file from sources on the ultimate dvd. other than that you will need to do full install.

There are only about 3 types of discs of Vista available(6 if you count the x64 flavors). each disc contains all editions. The key used during installation determines what features are installed.
Vista Home Basic, Vista Home Premium, Vista Business, and Vista Ultimate OEM
Vista Home Basic, Vista Home Premium, Vista Business, and Vista Ultimate Retail
Vista Enterprise (works similar to XP Pro Corp with activation)

If you want you upgrade from Vista Business --> Vista Ultimate your need a Vista Ultimate KEY not a Vista Ultimate DISC.

look into Vista Anytime Upgrade to upgrade your current installation to Vista Ultimate.

I have a Windows Anytime Upgrade disc, but I'm sure it's RTM media and produced the same greyed out upgrade option. Looking at the MS WAU website I see this:

All Windows Anytime Upgrade with Service Pack 1 (SP1) products will be updated with Service Pack 2 by the end of July 2009. In the meantime, if you decide to purchase Windows Anytime Upgrade with SP1, you will receive 32-bit DVD media and must have Windows Vista SP1 installed on your machine.

So it would appear that I need the WAU media to match the SP level of the installed OS. This makes sense.