MetroMon

If you need a metronome or a guitar tuner, MetroMon can be really helpful.

Although it's not a new program, it is very good as a metronome, you can choose tempo, beep length, the Hz of the different beeps and the beeps per bar.

If you want to use it as guitar tuner, it can help you, but there exist some other ones which offer more features. However if you need a simple and easy-to-use metronome and guitar tuner, MetroMon is a good choice.

Finally, it doesn't need to be installed.