Thanks for the response Paul!

After inserting the card, before installing the AMD drivers, the only issue I had noticed was the mobo’s splash screen appearing as such: http://i.imgur.com/2jiB7wG.jpg
I assumed this was simply a consequence of the missing drivers so I went ahead and installed them, which is when the other artifacts started appearing, and the hanging/crashing started happening.
I had been using an EVGA GeForce GTX 570 HD alongside Windows 7 in this build for 4 years with no issues. The NVIDIA drivers have been removed using the Display Driver Uninstaller I mentioned, although I did forget to do so before installing the new card.

Also, unrelated question, is there any way to delete comments on this forum? I accidentally posted this comment as a reply to my post rather than your comment, and I’ve only figured out how to remove the text rather than delete it entirely…