You download a "Labeljoy Keygen.exe" from a sketchy site. Step 2: Your antivirus flags it. You disable protection (first mistake). Step 3: The keygen shows a fake 'valid' code. You enter it into Labeljoy. Step 4: The software phones home, sees the blacklisted code, and disables itself. Step 5: Meanwhile, the keygen installed a background miner using your CPU.
Searching for "free" registration codes often leads to malicious websites offering keygens (key generators). These are unsafe and are not genuine registration methods.