A possible solution
My home network has a XP home desktop (wired) and Vista Laptop (wireless), Laptop always accessed desktop, desktop was hit or miss for getting to the laptop. Certain very useful tools (right click picture batch resize only on XP, not Vista...) Finally after months of running around, I turned off both firewalls, then the Laptop's window's explorer directories had a right click "share" option. Set sharing to the way I want it for EACH sub directory (downloads, games etc...) and finally the desktop "sees" all the laptop's folders and can access them. Now I'll turn the firewalls back on. No end of setting the Vista laptop folders to share wth right click/properties/share/advanced options helped until I turned the firewalls off, then right click had a "share" in the middle, not just the properties/share... (but do both to make sure).