Friend's computer infected; sending out countless e-mails

Greetings. It's been an age since I last visited Wilders, so I'm not sure you folks still provide assistance to people experiencing virus attacks. I'm writing on behalf of a business contact whose computer has been infected with a virus that is generating multiple e-mails to everyone in her address book.

All the e-mails contain attachments that have a ".txt" or "pdf.txt" extensions. Happily for me my e-mail client has prevented me from opening any of these attachments, but they are all tiny, none more than a dozen kilobytes.

The problem is the frequency with which her computer keeps generating these e-mails. I've received a dozen thus far, as have many or all of her clients. So far her own IT dept has been unable to come up with a fix.

Can anyone here shed light on what might be happening? And what advice I should give her as to how to stop this infestation?

I will gladly furnish whatever additional details you wish me to provide. Just let me know what further info I should ask her for.

Thank you,

Trist