what do the 2 green lights on the front of my desktop mean/represent?

[sufyanmess007]

i have a hp 6200 sff and there are 2 green lights, one of them flashes alot and the other just stays green, this may be a dumb question

 

[Darkbreeze]

One tells you the power is on. The other represents hard drive activity.

 

[sufyanmess007]

hmm, now i see whenever i open a game it goes louder and flashes less thanks.