I had that problem on a hard-working laptop leading up to a hard drive failure some years ago. A block of keys did not function.
The machine was used to doing a lot of grunt work, had high cpu temps and a noisy fan. It all recovered with a new drive.
Recently it started again and with not enough disk space to do a defrag, I removed a lot of data files, sufficient to enable a defrag, relieve a little bit of pressure, and heat off the machine and the keys recovered after a defrag.