To in-place Upgrade open the media, right click Setup to Run as Admin. If any hurdles then see these steps to overcome them: http://answers.microsoft.com/en-us/windows/wiki..
To Clean install using the bootable media follow these steps which compile the best possible install that will stay that way as long as you stick with the tools and methods given: http://answers.microsoft.com/en-us/windows/wiki.. : http://answers.microsoft.com/en-us/windows/wiki..
If you are governed by an organizations's Group Policy you must consult your IT department who may manage these updates. If this is a consumer licensed PC that shouldn't have Group Policy then I would do the CLean Install and wipe the drive to get it cleanest.
I hope this helps. Feel free to ask back any questions and let us know how it goes. I'll keep working with you until this is resolved.