For what it is worth, here is the general purpose way of doing Video card problems.
1.
Read the instructions. Unless you are a video graphics engineer, the maker of then card knows more than do.
2. If in doubt, do NOT install the card. First start with a very plain VGA card.
3. If you installed ANY specific drivers for ANY kind of video cards, remove then and their utilities.
4. Once you have a plain-Jane VGA card running generic drivers you can proceed.
Depending on the card, you may be told to install the CD programs before you install the new super duper card of you choice.
On a home built computer you sometimes can not start with a super-duper card, you have to start with a older VGA.
Read the documentation.The proper utilities for the card will do the registry stuff for you.
This general approach is valid for all current ATI cards in the consumer market.
But you can see for yourself...
Graphics - Desktop - AMD Support Search20870: Guide on how to install an ATI graphics card and / or its drivers ... This guide is meant to help you with removing an old video card and installing ...