If you have an earlier version of Office installed on your PC and you install Office Home and Student 2013, Office Home and Business 2013, Office Professional 2013, or Office 365 Home, you won't have an option to upgrade over the previous version. Instead, you'll have both the new version of Office and your earlier version installed on the same PC. If you don't want both versions, you should uninstall the earlier version through Programs and Features in Control Panel.
If you have problems uninstalling, use the Fix it in these articles to remove Office:
If you have a preview version of Office on your PC, like Office 365 Home Premium Preview, you must uninstall the preview first before you install a full version like Microsoft Office Home & Student 2013. If you don't remove the preview, you may get this error:
Microsoft Office 2013 does not support upgrading from a preview version of Microsoft Office 2013
If you already have a full version of the new Office product, like Office Home & Student 2013 or Office 365 Home on your PC and you want to switch to another version, contact support to learn more about your options.
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