A friend asked me this question, which I couldn't answer, after I recommended a variety of malware removal strategies to alleviate her fears that someone might have put a keylogger program on her PC.

Programs like Spybot claim to detect and remove keyloggers.

Keylogging software claimes to be undetectable by programs like Spybot.

Who is telling the truth, or is the truth somewhere in the middle?

What really is the best strategy for checking to see if anyone has installed a keylogging (or screen capture, or session capture, or whatever) program on a shared PC?