Overwrites files with other open document

[Barry Nicholl]

Running excel 2000 sp3 on XP V5.1 service pack 1

When I have 2 excel documents open and I click the close
button, one of the documents gets overwritten with the
information in the other. They both keep their names and
properties. Its as if there is a Save As getting invloved
or an entire cut and paste and then save. Anyone know if
it is a bug?

Thanks
Barry