UserEventAgent consuming 100% CPU

Mac Book Air is getting hot and fan running much more than usual. Flattening battery very quickly.

UserEventAgent and Kernel_Task are consuming 100% of CPU according to activity monitor.

It seems that:-

com.apple.UserEventAgent-Aqua.plist

com.apple.UserEventAgent-LoginWindow.plist

could be the files at fault.

I have moved them to the desk top but they also remain in place. I can't seem to remove, delete or rename them as the net advises.