It will throw an error because the activation code would be incorrect. However, LibreOffice is as good as MS Office if not better in some ways and it's completely free because it's developed in the opensource community.
It will work equally well in 32 or 64 bit systems and doesn't need activating. It will recognise and work with existing spreadsheets, documents and presentations which were created in Excel, Word and Powerpoint. You will need to tell Windows to use is as the default programme for .xls/xlsx, .doc/docx and .ppt/pptx.