it affects certain models of HP laptops(and Possibly other brands) using audio hardware made by a specific subcontracting company and the subcontractor's poorly written drivers. this isn't so much a company being malicious as being incompetent programmers. the software captures all keystrokes at all times(for the purpose of detecting if you wish to change volume using your keyboard), and then writes the data to an accessible log file on your machine.
If you see MicTray.exe, MicTray32.exe or MicTray64.exe, you probably are affected. if windows autoupdates are enabled, removing the driver will redownload it since it is signed by microsoft as an official HP driver.
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if you are infected, dealing with it is a lot like killing old school windows viruses. you will have to kill running processes, rename the .exes to be able to delete them, and then go after all the infected registry hooks.