HD 5870.

What do you guys think of my seventeen-months old build?

i7-5820K

Asus X99 Deluxe

Corsair 4x4GB DDR4 2400Mhz RAM

EVGA SC2 GTX 1080 Ti

Samsung EVO 500GB SSD

Corsair TX750M 750 Watt PSU

NZXT H440 Medium Tower

LG 43UH6500 43" 4K TV as monitor

I'll have to wait until I return home to provide pictures.

@_SKatEDiRt_: Maybe putting cards in their boxes after they've been used extensively is the problem, because when I decommissioned my HD 5870, which I've had since 2010, I never put it back into its box but have kept it atop my media shelf as a display piece and it still works.

@_SKatEDiRt_: I've pretty much given up on the card and have accepted that it's dead; I've been in denial. However, I'm perplexed as to how it died while in storage; it was working perfectly when I decommissioned it.

I removed the backplate and heatsink and then cleaned off the PCB with a compressed air canister. However, the card still won't post.

It was inside an anti-static bag for the entire time that it was in its box.

I want to use my old computer, which I built back in 2010 and whose HD 5870 I upgraded to an Asus DirectCU II HD 7970 in 2013, for cryptocurrency mining until I get a better card for that purpose (I have a GTX 1080 Ti in my most recently built machine but don't want to wear down said machine by using it to mine).

However, even though my display appears to detect the 7970 whenever I turn on my old computer, which it does by prompting me to switch to the input channel to which I have my old computer connected, the 7970 displays absolutely nothing and therefore causes my display to show a notification that says "No Input."

I know that the problem is the 7970 and not the old computer itself, because the old computer's video output works perfectly whenever I connect my HD 5870 to it. Furthermore, when I swap my 7970 with my 1080 Ti in my most recently built computer, it still fails to provide a video signal.

I don't understand why it's doing this, because when I decommissioned by old computer a year ago and placed my 7970 into its box, the card was working perfectly fine. So, I don't understand how it could have become damaged or defective since then.

By the way, the LED indicators above my 7970's power-connector sockets glow green and both the card's fans spin, which indicate that it's functioning and isn't dead.

So, what do you guys think is the problem?