How can I change my computer from a 32-bit operating system to a . . . Boot to the Windows 7 64 bit desktop, insert your Windows 7 32 bit DVD, click Run setup exe when the Auto Play dialog appears If you want, you can also boot from the Windows 7 32 bit DVD and also do a custom install Its just that, it’s a bit more elegant when you simply boot to the desktop and start the installation from there