There may also be a diagnostics program installed on the server which could pull out the info, but to run that you'll probably need Administrator access which I'd guess you don't have. This may also have either a green, orange or red light or be backlit in one of these colours. If it's one of the others, there may or may not be a front status panel giving more info, or even just an error code (e.g. You can recognise these cos the power leads are going into them. If it's a PSU these will slot into the back, and should again have lights. You'll be looking at a front-mounted drive caddy, with each HD in it's own slot, and each with at least one light, which may be green, orange or red. If it's a HD, and again depending on the make and model, there may be lights on the front panel to indicate this, and which HD it is. This indicates something that there is more than one of, commonly either a hard disk, a CPU (if more than one), a memory bank or a PSU. Now looking at the logic of it, the server is still running, so whatever it is that needs your attention is something that the server can remaining operating despite a failure or imminent failure of.

You need the make and model of the server first and foremost, as the beep codes could be different depending on these factors. Beeping is normally an indication that something needs your attention, but - as you've seen - determining what that something is can be a whole other world.