Found myself in this issue when doing a clean install to update my drivers in an attempt to fix an issue regarding OBS game-capture etc. However, now I've found myself in this mess.
Attempting to do an install of Radeon 18.3.4, getting the same issue with 18.2.1 if you're curious, through the full installer rather then the minimal one, and all methods end up giving a 1603 error.
In an attempt to fix this I have so far followed the entire support page that is linked when the error is displayed in the installer. (here)
This includes using DISM, SFC, fixing with C++ Redistributable, no due updates for windows, using AMD cleaning utility and also giving DDU a try, running if safe-mode of course. To clarify, neither DISM or SFC seem to find any issues and the other things I've attempted haven't resulted in any notable difference. I've also had xBox Game DVR disabled through regedit since long ago.
Furthermore looking up the Display Adapter in computer management it turns up as "Microsoft Basic Display Adapter" which when interacted with allows me to install/update drivers, both through internet and through local drivers which link me to my already downloaded AMD drivers. However this also results in an error which states that one of the installers can't perform the installation at this time, however I have yet to try this in safe-mode rather then running the ordinary installer in safe-more.
Using a HP Elitebook 850 running Intel Core i5 4300U with 8 GB's of RAM on Windows 10 64x. Radeon card currently in use is AMD Radeon HD 8750M
Thanks in advance for a possible solution to this issue.
EDIT: I have now successfully installed the drivers and software version 18.3.4 after running a reset reinstalling windows on the PC. However, the question of fixing such an issue still persists as even the drivers provided from HP for the exact laptop model refused installation.