A computer security system comprises a basic inputoutput system adapted to store a user key generated by a trusted platform module for a user. Embodiments may also include, for each phrase in the sets of candidate phrases, generating multiple component scores based on one or more of the frequency with which that phrase occurs in the item description information for the subset of items andor the frequency with which that phrase occurs in a corpus of item description information for the overall group of items. The exhaust valve is movable between an open position and a closed position. The binaural beat can be continuous or intermitten.