The video card may or may not be able to be saved.
Best thing you could do, is to find out if there's still warranty on the card, even when flashed.
But I wouldn't set my expectations too high on that.
Regarding the onboard. Have you tried removing the old video card before booting on the onboard?
If yes, try clearing the CMOS.
The card might still be able to be saved, but it requires that you had the wrong flash-file and the right flash-file, and of course you'll have to know what card it is.
Then you can boot the computer with the card in it, and flash the card (with blank monitor!) with the original flash-file, and if, and only if, the wrong flash didn't do any damage, you'll be able to restart after 15 min. and get a living video card again!
This also requires you to know what buttons to push while booting without any image.
The reason I wanted you to have the bad flash-file, is that you can edit it, to see if there's any damage it could have done. (Memory clock, etc.)
(Sorry about my english, I think i have a really bad evening!)