Every so often (hence 'randomly'), explorer.exe takes up 80+% of the computer's resources, instead of system idle process. It (explorer.exe) also takes up a lot of ram, like 36-60+. Rebooting helps, but I'm wondering if you can figure out what's the matter. My computer 'lags' a lot when this happens.
No I don't have viruses, spyware, or any other nonsense.