Microsoft is tight-lipped about the evidence, but Excel 97's macro virus checking is less than 100 per cent effective. Under certain circumstances ù if the Excel workbook is password-protected, for example ù a determined virus author can hoodwink Excel into running macro code without warning. Ordinarily, Excel posts a warning dialogue box that gives users the opportunity to prevent the macro from executing.

To fix the problem, Microsoft posted a 2.73MB patch at officeupdate.microsoft.com/downloadDetails/xl8p6pkg.htm. Because this patch works only with the Service Release 2 version of Excel, you'll have to update your copy of Office first (for details, see officeupdate.microsoft.com). All these patches are included on this month's cover CD.