Please help!

I have an Excel 2000 template that suddenly displays this
message when opening:

The macros in this file do not match the digital
signature. Only a macro with a virus would cause this.
Please scan for viruses.

As a company, we run TrendMicro OfficeScan, which doesn't
appear to detect macro viruses.

Any ideas how I can "save" this file? I do have a backup
but it's two days old. Thanks!

Cindy