You cannot do an upgrade from 32bit to 64bit. You will want to boot from the 64bit DVD and do a "custom install" This will wipe your drive clean so backup what you want to keep. If you have the upgrade disks, you will need to do the clean install but do not enter your activation code. When you are in 7, leave the disk in and then do an "upgrade" over your new installation and then enter your code. The reason is because you just did a clean install and your code is for an upgrade. If you try to enter code after clean install you will recieve error. Good Luck.