For years I have been using Office 2007 within Windows XP perfectly adequately, mainly Word and Excel. For the past few weeks however whenever I fire up Excel, directly or by clicking on an xls file, the program persists in going through first its Setup Process ("Please wait while Setup prepares the necessary files") followed by the even longer Configuration Process ("Configuring MS Office Professional Plus 2007 .."). Once this is completed things operate normally. This happens only with Excel not with Word. I must have inadvertently altered some setting.
How can I get back to the original state? It's too late for System Restore now.