Verified answer

Your current OS has to be a minimum of Vista Supreme

to be able to upgrade to Ultimate. XP, Home Basic are not upgradable to Ultimate. If your PC is compatible with the Upgrade, it will be a clean install. However, the OS you are replacing will be on your hard drive. You can delete it manually by going to your C drive and find the folder that is

titled, Windows Old. You can delete this folder like any other. Once done, you can never go back. But, if you leave Windows Old on your HD, you would be able to restore it

should you feel the need.

I did the upgrade. And what it does is Install a Ultimate. You will have a file called old windows, which you can keep, or remove after the upgrade. Your upgrade is stored on a digital locker. So you can always get to it.

I will be honest, if you have Home Prem---it is really not worth the upgrade. It has a few new items, but they did not add up to the extra money for the upgrade.

Hmmm,

Depends what your using your PC for,

If it's a gaming rig, I wouldn't recommend having Vista, Especially the Ultimate package, Because it uses up alot of ram, Unless you have more than 2.5Gb of ram I wouldn't do it,

But, If you upgrade it wouldn't erase you system, just back up your data just to be safe, or just go buy a whole new rig. :)

-Ak47