Changed Computer Name = Problems

I have changed the name of my computer and now I am having problems with
IIS.

I think it is something my IUSR and IWAN they
are still in the old computer name - should I just rename these.

The problems I am having are numerous, but let's start with the fact that I
cannot can open files in FrontPage, but I cannot save any changes. I get
the error message:

Server error: Cannot open file "c\inetpub\wwwroot\Default.asp" for writing.

PWS