XP Automatically installing Printers

Two Pcs connected to a local ethernet LAN within a
workgroup configuration.

PC1 has two printers installed, one being a TCP/IP LPR
printer.

PC2 was setup exactly the same but is now automatically
installing any shared printer from PCs (operating system
irrelevant)within the same workgroup.

Can delete and remove from registry but within days they
are back.

The are appearing as Lan Manager Printers/Ports.
Have checked LMHosts and no entries present.

now causing major problems as everytime this occurs it
knocks out the LPR printer

Can someone please shed any light on why this is
happening.

Thanks

Julie D