Microsoft is advising users to reinstall Windows if they happen to be unfortunate enough to get hit by a particularly vicious rootkit.

The Popureb Trojan sticks its tendrils so deep into the operating system that the best option is to nuke from orbit return machines to their original configuration. Any files that aren't backed up will be lost in the process.
MS advises drastic measures to fight hellish Trojan • The Register

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