black screen from gpu :(

[Blingbird]

i recently purchased an rx 480 from you and emailed a overclockers uk to ask if overclocking my card would void my warranty. he informed me that it would not. so i overclocked my card. then after doing this i reset the card to default clocks to check the performance gain , but after opening heaven benchmark it gave me a peach colour screen. i presumed it was a simple error and proceeded to restart my pc. however i just encountered a black screen. the lights on the card where working and the same for the fans. because of this i check my ssd (boot drive ) same for my ram (removing it 1 by 1 ) then re-installing it. then i took the graphics card out and connected the hdmi to the mobo. this worked. so i knew the problem was my gpu. i then went on my pc without my gpu and removed the overclocking software(tri-x) but it still didnt work. i then tried it on another pcie slot. it didn't work. then i tried it on my brothers pc with a different output , power cables and mobo and it didn't work. now i no longer no what to do and fear the card is dead. i have checked the card over and there is no damage to the capacitors. if you could help it would be a pleasure.

[Blingbird]

ps this was originally to the seller of this card at oc uk