Thanks a lot for the hint.
For those who are still struggling with this issue here are instructions for a remedy:
Go to the Task Scheduler (may be found under Administrative Tools from the Programs Menu)
Find the entry Task Scheduler Library/Microsoft/Windows/RAC and delete the task in the right pane.
In my case it was repeatedly triggered every hour and kept my CPU at 100%.
This will not actually remove the taskhost.exe but it will eliminate unnecessary Reliability Analysis Task process which is keeping the CPU at maximum rate.