Networking Vista to 2 XP computers (again!)

Like User earlier this week, I can't seem to fully share my new Vista
computer with 2 Windows XP machines. I've been reading through this
newsgroup, and am nearly cross-eyed from trying everything that I can. Why,
oh, why does Microsoft make it so difficult for one computer to read
*everything* on another?

When in Windows Explorer on XP, I can see Vista (L under 'My Computer' but
trying to access that drive produces the error "L:\ is not accessible.
Access is denied." Also on the XP, under 'My Network Places', I see and can
access 'MyWorks on Vista' [whatever that is] and 'Public on Vista' [which I
don't use]; I can also see 'LDG on Vista' but trying to access it results in
'\\Vista\LDG is not accessible. You might not have permission to use this
network resource. Contact the administrator of this server [that's me] to
find out if you have access permissions. Access is denied.'

I've been through all the suggestions I could find in this newsgroup -- same
workgroup name for all computers, network set to Private, all Sharing and
Discovery items (except Password protected sharing) are On. In Properties,
I've ticked everything relevant that I can find on the Sharing and Security
tabs.

What else can I do to allow the 2 XP computers to fully access the Vista
computer?

Lindsay Graham
Canberra, Australia