This post will show you multiple ways in two cases Windows button not working and Start menu not working.
you might get more information from theMiniToolwebsite.
Windows Key Not Working in Windows 10
Windows key is one of the core keys in Windows.

It is also named as WinKey.
Thus, it is vital that Windows key always work properly on any computer.
The following part will show you some solutions to repair Windows key not working in Windows 10.

In this way, you might check that Windows key is working properly.
Method 2: Adjust Registry
Windows Registrysaves function records of all the keys.
If you delete or modify the data for the Windows key, it will stop working.

it’s possible for you to correct the key data in the registry to fix this issue.
Step 1: PressCtrl + Shift + Escto openTask Manager.
ClickFileand then selectRun new task.

Step 3: Locate toHKEY_LOCAL_MACHINE>SYSTEM>CurrentControlSet>Control > Keyboard Layout.
Step 4: In the right pane, right-clickScancode Mapand clickDelete.
Method 3: Update Keyboard Drivers
Outdated or incorrect keyboard drivers can also cause this problem.

you could fix this problem by updating the keyboard driver.
Step 1: PressCtrl + Shift + Esctoopen TaskManager.
ClickFileand then selectRun new task.
Alternatively, you could simply press Win + R together.
Step 2: Typedevmgmt.mscand then clickOKto open gadget Manager.
Step 3: Under theKeyboardssection, right-click your keyboard and selectUpdate driver.
Step 4: SelectSearch automatically for updated driver software.
Step 5: Download and set up the driver update.
Step 1: PressCtrl + Alt + Deleteand selectSign out.
Step 2: jot down your password and pressEnterto sign on again.
Now you’re free to check theStartmenu shows up or not.
Step 1: PressWin + Xand clickWindows PowerShell (Admin)to open it.
Step 2: In the Windows PowerShell page, jot down the commandnet user newusername newpassword /addand pressEnter.
Replace newusername and newpassword with your actual user name and password.
Step 3: Reboot your rig and sign in by using new user credentials.
Right now, your Start button will start working.
Step 1: PressCtrl + Shift + Escto open Task Manager.
ClickFileand then selectRun new task.
Step 3: Under theSound, video and game controllerssection, right-click your audio unit and selectUninstall unit.
Step 4: ClickUninstall.
Step 5: Under theDisplay adapterssection, right-click your video card driver and selectUninstall gear.
Step 6: ClickUninstall.
Step 7: Reboot your rig
After you complete all the steps, Windows will install drivers again automatically.
If you are also facing this issue, try the methods this post offered.