Macbook Pro with abnormal CPU usage and unrecognised battery. How to alternative SMC reset
In the Apple Support article on SMC reset it reads "On MagSafe power adapters, the LED might change states or temporarily turn off when you reset the SMC.". Other than that SMC reset does nothing visible. So probably the reset is working.

It seems like the battery is dead. In that case the Mac will throttle the CPU to reduce power consumption. This explains also the high load. Since the battery is necessary to buffers peak loads, the MacBook relies on it to operate properly.

You must replace your battery.