Here's a simple solution to attempt to restore your icons to their former glory:
Download the program we will be using to restore the icons by clicking here and selecting 'Download ZIP' at the top right of the page.
Once the ZIP file has done downloading, extract it and find the cleariconcache.vbs
script file in the extracted folder.
NOTE: Some anti-virus programs may flag the script as a false positive; it is completely safe and there is no cause for concern. If your AV is interfering with the process, disable it until we are complete.
Save all of your work and exit ALL applications otherwise the script may not work properly.
Double-click the cleariconcache.vbs
file, and allow the program to run in the case of prompts getting in the way of you doing so.
You should now be greeted with the following dialogue:
Hold 'Ctrl' + 'Shift' and right-click the taskbar, then select 'Exit Explorer'.
Your desktop will now become black/unresponsive. Do not panic, that is intended. Now select 'Yes' on the dialogue.
The program will now do its job of erasing and rebuilding the icon cache, attempting to restore corruption and resolving any missing icons. Await completion.
NOTE: If the process could not be completed, it may be due to open programs actively using the icon cache. Please make sure that ALL applications have been terminated and then retry this process from the beginning.
Once completed, your desktop should have now returned to normal and your icons will have hopefully been restored!
If this helped, be sure to leave an upvote to allow this to benefit more people.
If you have any queries, feel free to leave a comment below and the community and I will try our best to respond.