Hello
Welcome to the Microsoft Community.
Regarding the disappearance of your computer's application icons.
Here are some possible causes and solutions:
Restart windows explorer:
Open Task Manager:
You can directly open Task Manager by pressing Ctrl + Shift + Esc
on your keyboard.
Locate Windows Explorer:
In the Task Manager window, look for a process named "Windows Explorer" or "Explorer.exe."
Select and Restart:
Select "Windows Explorer" (you may need to scroll down to find it).
Next, click the "Restart" button at the bottom of the Task Manager window.
You can try fixing it by opening the command line and typing these two commands:
Get-AppXPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}
for %i in (%windir%\system32\*.dll) do regsvr32.exe /s %i
And you may Perform a clean boot (microsoft.com) to see if it is normal, this is a troubleshooting step. In this mode, we can further confirmed whether it is caused by system problems or third-party software or personalized Settings. So please be patient.
Disclaimer: A “clean boot” starts Windows with a minimal set of drivers and startup programs. It helps to determine whether a background program is interfering with your game or program and to isolate the cause of a problem.
These steps of "clean boot" might look complicated at first glance. However, to avoid any trouble for you, please follow them in order and step-by-step so that it will help you get you back on track.
You can create a new local account by following the steps below and switch to the newly created account to see if the function is normal. Because this cannot be ruled out due to the wrong configuration. Visit Create a local user or administrator account in Windows - Microsoft Support for more details.
Create a local user account
Select Start > Settings > Accounts and then select Family & other users. (In some versions of Windows you'll see Other users.)
Next to Add other user, select Add account.
Select I don't have this person's sign-in information, and on the next page, select Add a user without a Microsoft account.
Enter a username, password, or password hint—or choose security questions—and then select Next.
Change a local user account to an administrator account
Select Start > Settings > Accounts.
Under Family & other users, select the account owner name (you should see "Local account" below the name), then select Change account type.
Note: If you choose an account that shows an email address or doesn't say "Local account", then you're giving administrator permissions to a Microsoft account, not a local account.
Under Account type, select Administrator, and then select OK.
Sign in with the new administrator account.
Note: If the new account is normal, please do not delete the old account before backing up the data of the old account to avoid any data loss.
Note: If the new account can install the feature normally, and you want to use the new account, then you need to understand that the user data in the old account (under the C:\user\ directory) will not be synchronized To the new account, you can only restore the data as much as possible by copying all the data (files, folders) under the old account to the new user folder and replacing the files/folders under new user account, then there is no guarantee of 100% success, including your User data from some Windows apps and all third-party apps in the old account won't sync. So please proceed with caution.
If there is anything not clear or I can't understand your problem, please do not hesitate to let me know.
Best Regards
Patch - MSFT | Microsoft Community Support Specialist