XP Home and Pro handle file sharing differently. XP has more options, 
and you can read about it here:
http://www.practicallynetworked.com/sharing/xp/filesharing.htm
The check box doesn't appear in Home.
In my experience, which is not vast, the access denied message is always 
  a firewall problem. I've also seen setups where a seemingly unrelated 
change can affect sharing in this way.
Look in the ZA log files, and you might find an answer or, just disable 
ZA temporarily.
Ethereal, a network analyzer, can also be a big help: 
http://www.ethereal.com/



Will Stephenson wrote:
> Hello all!
> 
> I have a client who has a three machine peer-to-peer network that is
> coordinated by a LinkSys router. The internet works fine, but one of the
> machines (an XP Home Dell with plenty of RAM - 512MB and HD space) is
> refusing to share - as in when trying to access the machine from another
> computer, the error message appears that you don't have the correct rights
> to access this computer. I have done the usual network stuff: hardware all
> works, firewall (ZoneAlarm) has the local network as a trusted range, the
> workgroup name is the same throughout the computers, file sharing and
> printer sharing are on (in fact, the printer is being successfully shared),
> and the particular folders that the client wants shared are set up to be
> fully shared. The other machines share fine, and the Dell can get to those
> shares with no problems.
> 
> Here's perhaps an interesting aspect to the problem: there is no check box
> choice to enable or disable Simple File Sharing. I had thought that XP Home
> always had that choice. Perhaps its disappearance is related to the Dell's
> sharing problem? Any ideas about that or anything else I may have missed?
> 
> As always, thank you very much for your time and thought about this.
> 
> Will Stephenson
> Acadia Technologies Inc.
> mailto:[log in to unmask]
> 
> There are as many paths to God as there are people to walk them. 
> 
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