Office 97 being wiped by a virus.

Has anyone come across a virus that wipes out Mirosoft Office 97 and Outlook? I have a user that has Win98 SE with Office 97 and Outlook installed. She also has pcillon antivirus installed. This last week her Microsoft Office dissappeared along withall file folders that where connected to Office. This week she tells me that her Outlook Documents have dissappeared. I have installed McAfee 5.0 and the latest DAT files and cannot find any virus on the machine. I have run McAfee from a boot diskette before intalling and have gone to NAI and gone through all of the virus stuff I can find yet nothing about this. Can anybody help?????