

First, make sure the edition of Windows 7 you are upgrading from is already activated (if its not you will run into complications and you might have start all over by doing a clean install). If the license for Windows 7 Professional you have access to is either a retail upgrade or full version, you can use the product key and Anytime Upgrade to move from Windows 7 Home Premium to Windows 7 Professional.

If your Dell came with Windows 7 Home Premium 64 bit and you would like to use your Windows 7 Professional license you bought last year, you can upgrade the install Home Premium to Windows 7 Professional using Anytime Upgrade: Windows 7 32 bit works on 64 bit processors but you would not be maximizing all the capabilities of your processor.
