If your Word documents suddenly have the file extention .exe, rather than .doc, and other files have been converted to link files, your PC has probably been infected by an autorun worm. Our Helproom expert explains what you should do.

QUESTION For several years I've been using a portable hard drive to store valuable data, but I recently picked up what I believe to be a malware infection. Microsoft Word documents now feature the file extension .exe rather than .doc, while other files and directories have been converted to link files. Please help me reclaim my files. Adeniyi Afonja

HELPROOM ANSWER This looks like the work of an autorun worm. Such malware is designed to infect shared files on a network, or those stored on removable devices such as your USB drive.

An up-to-date antivirus should be able to detect and remove this worm. Launch your security program, install any updates, then set it to perform a full system scan.

Autorun worms use Microsoft Word files as a vehicle on which to propagate themselves, rather than destroying the information stored within. By changing the file extension to .exe, innocent users wanting to open the Word document are tricked into launching the malicious code attached.

Because the worm doesn't tamper with the data stored within the Word document, your antivirus software should be able to clean the infected files and return them to their original state for editing.

McAfee's antivirus has reportedly recovered files damaged in this way; many other programs will also be up to the job.

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