Problem(s): Windows Update Failing to install updates (Error Code 641) & AMD Display Driver's "Partially Installed".
Solution(s): Enable Windows Installer service manually.
Windows 7 steps:
Press the Windows key.
Type services.msc and press enter.
Navigate to Windows Installer down the menu in Services (Local).
Double Click Windows Installer (Alternatively you can right click and then click properties on the drop-down menu.)
Make sure Startup Type is set to manual.
The note below contains some extra precautions I took that may be unnecessary, here's why; after doing some reading on the Windows Installer service, I'm 99% sure the default setting for the Startup Type should be set to Manual. Basically when it is set to manual, any applications that need to use the Windows Installer service will automatically start the service when needed. I've read this from multiple sources.
Note: I started the Windows Installer Service manually before attempting to check for new Windows Updates, I then chose the updates that I wanted to install, after they downloaded and the first part of the installation was complete, Windows Update suggested I restart my PC, I didn't do this just yet as I wanted to minimize the amount of reboots and understood that I could also remove the faulty display driver at this point, so I ran the AMD Auto-detect Software to remove the "Partially Installed" driver. This is when I restarted my PC to both complete the Windows Updates and finalize removing my display driver. The Windows Updates had successfully installed. AMD Auto-Detect Software had successfully uninstalled the display driver. I wasn't sure if Windows Installer would be disabled again so I manually started the Windows Installer service after noticing that it was off. I proceeded to re-open the Auto Detect Software and to my delight, the display drivers were installed along with AMD Radeon Settings etc.
Operating System: Windows 7 Ultimate 64-bit (6.1, Build 7601) Service Pack 1
Processor: AMD Phenom(tm) II X6 1055T Processor (6 CPUs), ~2.8GHz
Memory: 8192MB RAM
Available OS Memory: 8192MB RAM
DirectX Version: DirectX 11
Card name: AMD Radeon R9 200 Series (290), Display Memory: 4095 MB, Dedicated Memory: 3050 MB, Shared Memory: 1045 MB
Other things I tried while trying to solve this
I've tried using AMDCleanupUtility to remove the existing drivers, then restarting, then running the auto-detect software to install the up to date drivers and then restarting.
I've tried running all of the relevant software as administrator.
I've tried downloading and installing the driver removal software and AMD Auto-Detect software to a separate hard drive in case one of my hard drives were corrupted.
I've even used nvidea's driver removal tool as well just in case by some mad chance some nvidea drivers got installed and was confusing my graphics card.
I've tried running sfc /scannow in cmd, it found some problems and apparently automatically fixed them, I can't remember the specifics of the problems but it said they had been successfully fixed.
I ran CHKDSK. Resuls: https://pastebin.com/raw/MZcpKaRG
If you need anymore information from me just let me know