Is svchost.exe a harmful virus?

Is svchost.exe a harmful virus?
Yesterday,I used my computer and I noticed a problem. A file or program called "svchost.exe." I think it eats my processor up to 30%. I cannot stop the process because it wouldn't allow me. I also cannot restart the process so what I did was to restart the whole system to be able to check if its going to show again. After that I clicked on the yes button to be able to stop the process but nothing happened.
Is there anyway in which I can stop showing the program or stop it?
Is it a harmful virus?
