Go to control panel - set program access and defaults - associate a file type - this will give you the set associations screen. Associate Microsoft Programs, If you don't own Microsoft Office or Word you can download a FREE copy of OpenOffice, it will read and write all Office file types.
it is obvious that your Microsoft office 2003 has been affected, remember in other cases when you can install an anti-virus later after you have installed an operating system it can delete data or corrupt, so it is important for you to uninstall that Microsoft office 2003 and install.
You must make sure you have spelled out "word" correctly in order for outlook to recognize it. Once spelled out correctly proceed to search for the word again.