My friend had a AMD Radeon HD 5750. He was looking to upgrade is his PC, so he went looking at his PSU to see what brand it was, as he he bought it prebuilt and wasn't sure. Upon looking at his PSU he noticed a switch that had no labels.Being the idiot he always is, he flipped the switch. his whole system shut down and wouldn't turn back on. So he ordered a new PSU and installed it. When he tried to turn it on, he said his motherboard gave off an amber light and made a beeping noise. He decided his system was broken, so he just bought a whole new system. He gave me his old GPU, the 5750.So I want to know if this GPU is broken, can it harm my PC, and should i even use it?