That means that it somehow (only you know how!) ended up as the default template normal.dot.
The only thing you have to do is find it (using My Computer or Windows Explore); in Windows XP it's C:\Documents and Settings\<username>\Application Data\Microsoft\Templates\normal.dot, but it might be in another folder in Windows 2000. When you've found it, delete the file. Word will make a new empty one.
I am using office 2000 professional and Windows 2000. A Word document that was saved has become the default document every time a new Word document is started. I have tried to delete the saved document, rename it and save it blank but without success so far--the previously saved document keeps on appearing. Does anyone have a possible solution? thanks.