Hi there, and welcome to AO

As far as I am aware "ShellNew" is something to do with the context menu of Windows Explorer (right mouse click options), and has been around since Windows 95 at least?

Of itself, it is harmless, I would have thought; and it might be that he set it up to give him an option to choose what application to open office type files with?

Obviously, that doesn't mean that he hasn't installed something malicious, but I cannot understand why he would install it there. Perhaps you might experiment a bit with opening Windows Explorer and right clicking on various filetypes to see what options the context menu brings up?