Apps not working in Windows 10

I upgraded my desktop PC from Windows 7 to Windows 10 Home last October.

After the recovery period was over, Windows 10 started acting up.

After a system upgrade, many of the apps stop working.

These apps include Windows Store, Mail, Calendar, Calculator, etc.

Instead of Mail & Calendar are now showing as "@{microsoft.windowscommunicationsapps_17.6416.4200" in the start menu, while Windows Store is showing as "@{Microsoft.WindowsStore_2015.23.23.0_x64_8wekyb3d".

I don't know whether other system apps are also not working.

I ran the system file checker in administrator mode and the resulting log file has 80K+ lines.

Trying to run Windows Store troubleshooter but it says Microsoft Account required.

I DON'T WANT TO SIGNIN WINDOWS USING MY MICROSOFT ACCOUNT!

When I use Add-AppxPackage to re-register these apps, I got various errors, such as merge failure with C:\Program Files\WindowsApps\Micro...\resources.pri, or the manifest file not found (due to corrupted install location).

Here are the Get-AppxPackage output for Windows Store and Calculator:

Name              : Microsoft.WindowsStore
Publisher         : CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US
Architecture      : X64
ResourceId        :
Version           : 2015.23.23.0
PackageFullName   : Microsoft.WindowsStore_2015.23.23.0_x64__8wekyb3d8bbwe
InstallLocation   :
IsFramework       : False
PackageFamilyName : Microsoft.WindowsStore_8wekyb3d8bbwe
PublisherId       : 8wekyb3d8bbwe
IsResourcePackage : False
IsBundle          : False
IsDevelopmentMode : False
Dependencies      : {Microsoft.VCLibs.140.00_14.0.22929.0_x64__8wekyb3d8bbwe,
                    Microsoft.NET.Native.Framework.1.1_1.0.23115.0_x64__8wekyb3d8bbwe,
                    Microsoft.NET.Native.Runtime.1.1_1.1.23406.0_x64__8wekyb3d8bbwe,
                    Microsoft.WindowsStore_2015.23.23.0_neutral_split.language-ja_8wekyb3d8bbwe...}

Name              : Microsoft.WindowsCalculator
Publisher         : CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US
Architecture      : X64
ResourceId        :
Version           : 10.1512.4020.0
PackageFullName   : Microsoft.WindowsCalculator_10.1512.4020.0_x64__8wekyb3d8bbwe
InstallLocation   :
IsFramework       : False
PackageFamilyName : Microsoft.WindowsCalculator_8wekyb3d8bbwe
PublisherId       : 8wekyb3d8bbwe
IsResourcePackage : False
IsBundle          : False
IsDevelopmentMode : False
Dependencies      : {Microsoft.VCLibs.140.00_14.0.22929.0_x64__8wekyb3d8bbwe,
                    Microsoft.WindowsCalculator_10.1512.4020.0_neutral_split.language-ja_8wekyb3d8bbwe,
                    Microsoft.WindowsCalculator_10.1512.4020.0_neutral_split.language-ko_8wekyb3d8bbwe,
                    Microsoft.WindowsCalculator_10.1512.4020.0_neutral_split.language-zh-hant_8wekyb3d8bbwe...}

Since this is an upgrade from Windows 7, I have a large number of programs already installed. I would not consider re-installing Windows 10 as a viable option. If I have to re-install everything, I might as well switch to a Mac right now.

Any help is greatly appreciated.