can ping but not connect / map other PC on XP PRO

I ready an earlier tread with huge interest, because it seemed to exactly describe my current problem.
Since a week or so I cannot connect anymore to my other PC within my LAN.
I can ping, even with the PC name.
I tried all stuff suggested, like:
– telnet
– hkey_local_machine\system\current control set\control\lsa -> restrictanonamous key
and changing the 1 (if present) to a 0.
(but that was already set at 0)

=> so the trouble must be caused by something else, hence also the solution…

Any help?

Pascal