X97M/Smack is an Excel 97 macro virus.
Disinfection & Removal
When an infected workbook is opened, X97M/Smack.A disables the built-in macro virus protection of Excel and removes the "Tools/Macro..." menu.
Then the virus copies the active workbook to Excel's starup directory as the name "XLDATA.XLS". After this has been done, the virus infects all workbooks that are opened.
It activates its payload at September 10th. At this time it shows a message box with the following text:
You know what? You're getting OLD, man!!!
Technical Details: Sami Rautiainen, F-Secure