After you install an x64 version of Windows on the same partition as a 32-bit version, you experience some or all of the following:

- Some programs become unstable.

- The 32-bit version of Windows does not start.

- The Program Files folder contains some 32-bit and some 64-bit files.

This problems will occur if you install an x64 version of Windows on the same partition as your 32-bit version.

While dual-boot environments are supported, you should never install more than one operating system per partition.

To resolve this problem, reinstall the 32-bit operating system and then reinstall the x64 operating system on a separate partition.

NOTE: When configuring a dual-boot environment with both 32-bit and 64-bit operating systems, install the 32-bit operating system first. The 64-bit version of NTLDR can also load a 32-bit operating system, but the 32-bit version of NTLDR cannot load a 64-bit operating system.