So i bought a used ups from my friend and its already 11months with me. During the first 5 months every time the power comes off it gave me the normal *tiiiit sound that all ups does. But, lately whenever the power is out it gives a small *tiiiiit sound like an old man dying or something. So what's the problem with this? Should i replace it or get it fixed? And one thing... will it affect my pc bad if it shut down during shutting off process it happened like twice now...