I just gotta say that it amazes me how anytime anyone ask about hiding an app or making an app difficult to terminate they get pounced upon. There are MANY valid reasons for making apps hard to terminate..let's take one.

I own a pc but I let someone else use it from time to time - maybe it's Joe from down the street, maybe it's Jr or Sissy down the hall. If there is any application which I determine should be operating at all times I should have the option of preventing the person who is borrowing my pc from terminating that app - whether it be antivirus, a firewall or a do-wop diddy wav blasted at full volumn every 30 seconds. It's my pc, not theirs. If they don't want to hear do-wop diddy they can just stay off of my pc - I'm kinda partial to do-wop diddy ad really love annoying the blazes out of folks by playing it repeatedly. Not to mention that it alerts me when one of the kids is on the pc.

Again, in case anyone missed my point, there are at least 42 gafrigginzillion valid reasons for an application to be required operational on a pc even if "Windows doesn't require it".