Unfortunately, you can’t change Windows 7 from 64-bit to 32-bit that easily. In fact, it is impossible. Windows 7 64-bit is capable of emulating Windows 7 32-bit programs, however you can’t simply change from 64-bit to 32-bit. Instead, you will have to purchase Windows 7 32-bit separately and install Windows 7 32-bit just as the 64-bit edition.
Tip: Before rushing into the stores to grab a copy of Windows 7 32-bit, consider upgrading your RAM to 4GB or more in order to run Windows 7 64-bit, which is clearly the preferred solution. There are virtually no compatibility issues and finding drivers for Windows 7 64-bit has never been easier.
If you still decide to get a copy of Windows 7 32-bit instead of a hardware upgrade, my tip is to create a new Windows partition and then install Windows 7 32-bit on a new partition. Then you can run both Windows 7 editions and you won’t waste too much time, creating backups and starting all over again. If you decide that this might be a good idea and you want to dual-boot Windows 7 64-bit and Windows 7 32-bit, read our tutorial How to dual-boot Windows 7 .