Some users will have a processor capable of running the 64-bit version of Vista but have the 32-bit version installed by default. This won't cause any problems, but it does mean you may miss out on some advantages (such as being able to utilise large amounts of memory). If you are in this situation, you can check to see if your computer can handle the 64-bit version of Windows Vista using the following steps.
First, open the Control Panel by clicking on the Start Menu > Control Panel.
Then click System and Maintenance.
Then select Performance Information and Tools.
This will display your computers performance index rating, allowing you to View and Print details.
In the System information section, you will notice a "64-Bit Capable" box. If this says Yes (like below), then you can run the 64-bit edition of Vista.