How do I stop hntwhlpr using 100% of resources?

Just happened today.

Rebooting didn't help, the process started up again immediately, and of course it's protected so I can't kill it. It's been an hour and the process is not stopping, it's just slowly eating more and more memory. My computer is old and it's so bad I can't even screenshot - had to take a photo of the monitor!

How do I kill this blasted process?