So the circle is where a little speaker should be attached:
Sometimes these come with the case, but in your case not apparently or the PC guy would have attached it. You can buy these pretty cheap (one or two bucks) and they look like this:
When you have one attached and start the PC the mainboard will run some tests, and if it detects a problem there will be a pattern of beeps coming out of the speaker. You can look up what this pattern means in the handbook somebody linked above.
Yes, but whether you have lights or just beeps depends on your board. I think yours does not have the lights, just the speaker pins.