This is necessary as the registry keys, shared programs, and file extensions are managed separately for each version. This would also apply to any standalone Office programs, i.e. You would need to install the oldest version of Office first (for example, Office 2003 would need to be installed before Office 2010).Instead, in cases where two versions of Office are needed, it is recommended that one version be run in a virtual environment (for example, using Windows Virtual PC which is explained in Microsoft KB 958559 ). While this configuration is possible, Microsoft does not recommend running multiple versions of Office on the same system.If you wish to install multiple versions of Microsoft Office on the same computer, take note of these important considerations: This article is meant to provide basic guidelines and information should you wish to utilize a multiple Microsoft Office configuration. NOTE: Dell does not support the installation or use of multiple versions of Microsoft Office.