Is there any use for a dead GTX 280?

[Luke122]

I'd return the card to stock cooler for sure. It's very possible that it's overheating before it can post!

Also, as mentioned, once it's returned to stock, try booting the system with a second GPU in there, and see if the system recognizes the "faulty" card.

[Kayin]

I fixed a pair of 4870x2s with the oven trick after a botched pair of WB installs. Also, I received an 8800GT that succumbed to g92 failure and was able to bring it back with that trick as well.

At this point, it's free and worth a try.