5870 Bad Flash help please

[zalbard]

Flashing should be possible in most cases, yes.
But really, it depends on what happened to the card. If it's a corrupt BIOS data (which I am assuming it is) then it should be flash-able, but if your BIOS chip went poof for some reason then you might have to seek RMA help (which should be a piece of cake if your store is close by).
And nope, no idea how to figure out which one exactly it is. But seems like 'normal' corrupted BIOS data to me.

What I don't get is why your PC does not boot with 2 cards installed. Especially since you said you used the replacement card in the top slot with monitor cable plugged into it...

But I have tried blind flashing using the CD nothing was happening so I used the 1650 to see why, no commands worked so I looked in DIR and there is no ATI Flash or BIOS, I made the disc using Nero 9 and added everything to make a boot CD.

Just use your replacement card for now I guess. Try to create a proper image and everything set up.
And if you're sure that your PC does not POST with 2 cards installed, just do blind flashing again, this time being sure that you're doing the right thing.