Printer occassionally stops printing

I have a printer HP LASER JET 2430 connected thruough a usb on a PC to act as its server.All my pcs are on a domain.The rest of the pcs on the domain access the printer through this machine.To connect a PC to the printer,I browse my network places,locate the pc with the printer,open it and just double click on the shared printer.
What is bothering me is that,occassionally and more so more often,some computers fail to print after sometime,they need me to go through the same process again by browsing my network places.
What could it be?Could it a virus,I have tried to rule out this.
Can anyone may be have another way of connecting the other machines onto the printer.
Thanx