Windows key not bringing up start menu

As the title specifies, my windows key does not open my start menu at the moment. windows+tab does the cascading tabbing of applications, windows+e opens explorer, windows+t loops through my task bar, etc. The only thing the windows key doesn't do at the moment is opening the start menu.

Rebooting would most likely fix this, I'd be surprised if it didn't. However, if rebooting right now was not an option (and it might not be one if I had a bunch of calculations running, but this is hypothetical, but I'd like to be prepared in case this happens), which settings should I check to fix this? I did try disconnecting and reconnecting the keyboard.

Although this may be overkill, I'd not say that there's some malware that specifically prevents you to do that, but maybe an app that interfers with the expected behaviour:

1. Run a check using anti-malware tools, like Adwcleaner or MalwareBytes, just in case.
2. Open the msconfig utility: Win+R and execute msconfig.exe.
   • Disable any unwanted applications that run on stratup.
   • On the Services tab, disable any unwanted services that run at startup too. You may want to mark the Hide Microsoft services so that you don't disable anything important accidentally.
   • By default, the msconfig utility marks the disabled services as Disabled, which means that you can't execute them even manually. Alternatively, you can execute the services.msc utility so that you locate such services and change their state to Manual, so they don't run on startup automatically but you'd still be able to start them if you need them.
3. Reboot and see if something changes, then you can start re-enabling services and apps on startup until you detect which one is causing you trouble.

There are many causes to the behaviour you experiment and these are some steps that may come in handy to detect your issue, but of course it's not the only solution.