The life span of the card has many variables affecting it; whether it was OCd, how dusty your case interior is, how much time the PC was on, how much time it was under load, even the quality of your PSU, these things all have a part to play.
Assuming the card does still work (up until the point it fails again, naturally) I'd monitor the gpu core temperatures using a program like MSI Afterburner. Check temps. Under max load (stress test) you should see at the very most temps of around 80c if you're factory overclocked. If temps are above that, there's your problem, but fear not, it may be that applying new thermal compound to the gpu heat sink solves temperature problems. Search youtube for a guide how to do that if unsure. Try that before buying a new card. It's worth noting that a card can handle temps of even up to 90c, but if the card were to regularly sit at such temps it would kill the card way quicker. If temps are that high it could be why it failed. Could also be that it was simply the card's time to fail
If temps are not a problem then check the power connectors to the card are in securely, remove dust from the card (if any) - never hurts to take it out of the case and blow into and over it with an air duster every 6 months to a year. Still having problems? Then might be time to get a new card.
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How does that even happen? The core temps of the GPU are way hotter than the rest of the card. There's no way a hot GPU can somehow fry an HDD which is located elsewhere in the case. Your gpu would literally melt before any heat from it even came close to superheating the air in the case to a temperature capable of damaging an HDD, unless the HDD was quite literally touching the GPU, which would be dumb.
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Before baking it at the very least I would try a. De-dusting it, b. refreshing new thermal paste on the heatsink, c. monitoring temps using software on the desktop under various conditions and d. check it isn't running at some dumb overclock frequency (which may have been triggered accidentally or while drunk or whatever)