Lost Connections

I have added 5 XP Pro Laptops to our Win 2003 Server, Active Directory Domain
that otherwise hosts 23 Win2K desktops and a number of printers including 3
HP 4100tn printers that are connected using JetDirect. The HP 4100 printers
were added to the Domain Controler's printers and then shared. All machines
are connected to one or more of the shared printers via the DC. The XP
machines do not maintain a connection to the Hp 4100 printers. However, a
quick reboot (not so quick) restores full connection to all printers. I have
checked network browsing durring these occurrances and I am able to do so
just fine. I have spent many hours trying to find the source of this problem
and have not successfully done so. HELP! And thanks in advance.