can`t map network drives of a cloned windows computer

[adumi]

Having backuped up my C drive (xp installed on it) with Nero backup and having later on used this backup to restore it - I stumble on the following problem:
I cannot map it`s drives from the local network other computers (also running XP).
I get:

The mapped network drive could not be created because the following error has occured:
Logon failure: the user has not been granted the requested logon type at this computer

the other xp machines are connected to it via a switch and can share it`s internet connection(it connects to the internet via an extra network card)
but they cannot map it`s drives or share files with it.
the cloned windows machine CAN however map the other network drives and share THEIR files.
This is not a firewall issue as the problem persists even if firewalls are down or allow access of the aforesaid cloned pc IP.
This is not a virus\trojan problem as I scanned the machine with various scanners.


What do I have here ?

Thanks in advance