Finally I have something to say. It seems that this problem is related with the "ForceGuest" feature, but I am not completely sure. My situation was more complicated that the one I wrote in my note: many computers and what I really wanted was to share the printers..., but I saw that no files were accessed outside any Win-XP computer. What happened? - I checked that under Local Security Policy was enabled the directive "Network Access: Force Network Logons using Local Accounts to Authenticate as Guest" - I checked that while sharing the Disk C, the group "Everyone" had premissions to read and write Now one of the computers (and it printer) can be accesed from the rest of the computers. There is still another one with this problem, but I move the printer to other computer. Sorry I cannot tell more details, due to my lack ok knowledge, of both the Windows XP inner functioning and the difficulty of the translation of the Spanish messages and errors to English. :cry: Elena