Doing a google search for error code 43 suggests it's a
driver issue. One suggestion is to uninstall the device and
drivers, then restart and DO NOT allow Windows to search and install any
drivers, then install the latest ATI Catalyst (which includes the
drivers).
You can uninstall both the device and the drivers in the Device Manager. RIGHT click on the HD4670 (to highlight it) then LEFT click "Uninstall" and check the box to also uninstall the Drivers. Then restart the PC and install as noted.
(I have an HD4850 installed in my Win 7 64 bit system).