What it doesn't do is ID the keylog program-- just tells you if there is a log being generated. So, even if you have a keylogger all this will do is confimr it (and give you the name of the log file). You still have to somehow track down whatever program is keylogging you.
You can easily test on your own whether there is a keylogger on your system without the detector (go to a website, type in some jibberish as a psssword, then hit "enter", then do a computer search on the jibberish phrase and see if there is a log file on your computer containing the phrase).

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