If you cannot hear your metronome while recording in Guitar Tracks Pro 2, try the following steps;
1) Go to Options | Click. Make sure that the Recording box is checked. If you want to hear the metronome from your computer case, check 'Use PC Speaker'. If you wish to hear the metronome from your computer sound card and attached speakers, check 'Use MIDI note'.
2) If you are using your sound card to play the metronome, you must choose a Port. You will want to choose an FM Synthesizer, MIDI Synthesizer, or GS Wavetable Synth. You do not want to use MIDI Mapper, SXG Synth, Virtual Sound Canvas, S/W Synth, or other software based synthesizers. Also, do not use MIDI Out or MPU-401.
3) If you still cannot hear the Metronome from your sound card, go to Start  Programs | Accessories | Entertainment | Volume Control. This can also be reached by double-clicking the small speaker icon next to the clock in Windows. The opening screen is the monitor/playback level control. Go to Options | Properties and make sure that everything is checked under 'Show the following Playback Controls'. Click OK. Make sure that the MIDI/Synth Slider is turned up and not muted. That should solve any metronome related issues.