Most utilities at Funduc Software are available in separate 32-bit and 64-bit versions. If you are running a 64-bit operating system and if a 64-bit version is available, that version is required.
Beginning with Windows 7 the majority of computers in the US are shipping with 64-bit Windows.
If you do know which operating system you have, follow these steps:
1. Go to Start Menu -> Settings -> Control Panel
2. Click on 'System'.
3. If your computer is running Window XP, click on the General tab.
4. Examine the information you see under 'System'. If there is nothing listed indicating 'x64 edition version' or '64-bit Operating System' then you have a 32-bit Windows installation.
For further information please see Microsoft Help and Support Article ID: 827218 - How to determine whether a computer is running a 32-bit version or 64-bit version of the Windows operating system.