Is KMS activation illegal?

The KMS technology itself is a legal tool created by Microsoft. However, using it on a personal PC without being part of a legitimate organization that owns the volume license is a violation of Microsoft's terms of service. Using a pirated tool that emulates a KMS server is illegal and unsafe.

Will my PC stop working if my KMS activation expires?

No, your PC will not stop working. Windows will enter a 'notification' mode where you will see a persistent watermark, be blocked from personalization settings, and receive regular pop-ups reminding you to activate.

How can I check if I have a KMS activation right now?

The fastest way is to use the command line. Open Command Prompt as an administrator, type 'slmgr /dlv', and press Enter. A detailed window will appear. Look for the 'Product Key Channel' line. If it says 'Volume:GVLK' or 'Volume:KMSClient,' you have a KMS activation.

I followed the steps to remove KMS, but the 'expiring license' error came back. What happened?

This is a sign that you used a pirated activation tool that installed a malicious service on your PC. This service automatically re-applies the fake KMS activation. You will need to run a deep scan with a reputable antivirus and anti-malware program to find and remove the malicious script.