Hello there,
I recently encountered same problem. i had to perform System recovery, because my Windows woudln´t start up, and since then my CPU is between 40-100% of it´s usage, google chrome is lagging, stops responding and working with it becomes very unpleasant. Looking at task manager doesn´t really help, except chrome there´s nothing consuming memory, really, and anyway, bedore it didn´t matter. Woudln´t anybody know what is the problem? I scanned my computer for viruses, scanned with Advanced System care as well, and it doesn´t find any negative issues.
Arrxen