Really thanks for trying to help, i got the exact same downloads (and many others) as mentioned the official 13.4 is not supporting the agp version of my card but just the pci-e and auto detect works only for Win10\1. In some cases you can try to force a manual install of the drivers but in my case resulted in a loop bsd that i manage to overcome only by deleting everything that had to do with ati\amd from my system. After that i downloaded everything i could find from 09.8 (that i had from my previous ati gpu) to 12.3 and i went through the very painful exercise of identifying one by one the best suited for my system. For the time being i have settled with 10.9 that support perfect mode. it seems that some 2011 drivers are better however my system don't digest them and with them i have a number of glitches, bsd, slow motion fps and again i had to wipe my system clean and reinstall 10.9. In all this my soundblaster audigy was also affected and i had to revert to the il2 2006 mg_sound dll to get everything back.
The big problem with unofficial driver downloads is that they are often incomplete so even if the driver itself works then ccc is not working or that drivers have been "modded" or adapted somehow and of course not signed and not whql compliant therefore the problems with system instability. That is why i think is a pity that a big and lucrative company as AMD didn't bother to mantain an historical archive with a very limited additional cost and wouldn't take more than a couple of hundred g of server space. This could have helped a lot their clients and i am sure that the community would have appreciated and most likely increased the use of their products. As mentioned in one of the post linked by you it is much easier to download old drivers for Nvidia and it took me less than three minutes to find the last working version (together with the previous ones) for GeForce 550m ,win7 13 year old, all official all signed all whql.