Put the 5770 back in and verify that the Web Drivers are still booting by default.
Make sure you have card securely installed.
Check to see if you have busted off any components. in my experience, the most common cause of a dead card (and I mean DOA to the world) is when someone just misses the slot and rakes the tiny line of components on back side of card over the slot edge. Dislodging just one of these can cause card to vanish.
Can you just leave the 5770 in and try both together?
Make sure you have card securely installed.
Check to see if you have busted off any components. in my experience, the most common cause of a dead card (and I mean DOA to the world) is when someone just misses the slot and rakes the tiny line of components on back side of card over the slot edge. Dislodging just one of these can cause card to vanish.
Can you just leave the 5770 in and try both together?