mail merge in office 2000, suddenly freezes

I have been using mail merge for well over 8 years. Never had an issue. All of a sudden it freezes after I select a data source. I have no option but to “x” out of it. The odd thing is that a blank EXEL spreadsheet remains open, which I then have to close. I am stumped as to why this started happening all of a sudden. ANY help or insight on how to fix this and why it suddenly started happening would be appreciated