The option of purchasing an upgrade over the full version of a new operating system is often the preferred method as it is alot cheaper, but update versions tend to be a little more problematic. For example, if you wanted to do a clean install of your new os you had to prove that you qualified for the upgrade by inserting the original cd of the older os at some stage during the install.
The upgrade version of the new Windows Vista has done away with this CD check for doing a clean install, but to use it you still need qualifying software, such as Windows XP or Windows 2003. But here is the good news – Windows Vista upgrade version also accepts an ‘unactivated’ version of Vista! That means that you can clean install your upgrade version of Vista without activating it and then ‘upgrade’ this install to the upgraded version. The downside of this means you have to install Vista twice, but Vista installs faster than XP, and you can save as much as 50% of your cash in the process.
Step 1. Boot the PC from the Vista Upgrade DVD.