Thanks very much, Peace. (I do have XP.)

The site says:

"Can I delete it?

You can remove this account, but it is vital if you do asp.net development work on your machine.
By removing the account you may find your ASP.net projects will no longer function correctly."

I have no plans ever to do any ASP projects. Meantime, I'm glad to hear I have not accidently removed my computer's liver.