How many computers can you use vista upgrade on?

i am about to order the vista upgrade to upgrade from vista i was wondering how many computer i can use the upgrade on because i have a few computers. thanks

How many computers can you use vista upgrade on?computer virus

Only 1. I assume you're upgrading from one version of Vista to another. If you're upgrading from XP, make sure your system has enough horsepower before you attempt this--it's hard to go back. You'll need 2.0Gb of RAM and a reasonably fast processor along with a pretty good graphics processing unit. All of the new systems come with these features already, but only better XP systems do. Without them you'll be as frustrated as many ''Top Contributors'' that have had their day spoiled by a slow system or one that didn't work like XP.

Vista is the gateway to all of Microsoft's new applications platforms. The public has not even begun to see the innovative and brilliant new programs and support systems that are in the pipeline being built by Microsoft and third-party application houses--very few of these will will run on XP--no matter how much RAM you have.

From the Vista Ultimate EULA (I expect all versions would be the same).

2. INSTALLATION AND USE RIGHTS. Before you use the software under a license, you must

assign that license to one device (physical hardware system). That device is the 鈥渓icensed device.鈥?br> A hardware partition or blade is considered to be a separate device.