Scammers are trying to trick Windows users into paying to fix bogus hard drive errors that have apparently erased important files, a researcher said Monday.

The con is a variant of "scareware," also called "rogueware," software that pretends to be legitimate but actually is just a sales pitch based on spooking users into panicking. Most scareware masquerades as antivirus software.

But Symantec researcher Eoin Ward has found a new kind of scareware that impersonates a hard drive cleanup suite that repairs disk errors and speeds up data access.

Dubbed "Trojan.Fakefrag" by Symantec, the fake utility ends up on a Windows PC after its user surfs to a poisoned site -- often because the scammers have manipulated search engines to get links near the top of a results list -- and falls for a download pitch, typically because it's presented as something quite different, like video of a hot news topic.

Fake system or disk cleanup programs aren't new -- Symantec has highlighted the scareware subcategory before -- but this malware goes above and beyond the call of counterfeit duty.

"[Trojan.Fakefrag's] aim is to increases the likelihood of you purchasing a copy of Windows Recovery by craftily convincing you that your hard drive is failing," said Ward in a company blog Monday, referring to the name of the fake suite that the Trojan shills.

The malware kicks off the scam by moving all the files in some folders to a temporary location, by hiding others and by making desktop icons disappear. All of that is followed by a message that looks like a valid Windows warning of impending hard drive doom.

"An error occurred while reading system files," the on-screen message reads. "Run a system diagnostic utility to check your hard disk drive for errors."

If the user clicks "OK," the fraudulent "Windows Recovery" application launches, runs a series of sham scans that sound technical and legit, then reports multiple problems, including disk read-write errors.

With the hook set, the scammers try to reel in the victim by trying to get them to pay $79.50 for Windows Recovery, which will supposedly fix the make-believe issues.

Since the user has just seen his files and icons vanish, he or she is much more likely to fall for the scheme.

"It does a really convincing job of making it appear as though something is wrong," said Ward. "When it 'deletes' files from your desktop, it does so in a very prominent way."

No surprise, but the files aren't deleted; they can be found with a quick local search, said Ward.

Windows isn't the only operating system targeted by scammers. Last week, for example, Intego Security reported finding the first-ever Mac OS X rogueware .

Scammers have upped their "scareware" game by convincing Windows users that their hard drive is ready to croak.

Gregg Keizer covers Microsoft, security issues, Apple, Web browsers and general technology breaking news for Computerworld. Follow Gregg on Twitter at @gkeizer or subscribe to Gregg's RSS feed . His e-mail address is gkeizer@computerworld.com .

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This story, "Windows Scareware Fakes Impending Drive Disaster" was originally published by Computerworld .