Network Printing Issues. we have the 6100 as a network printer in our office. one computer sees it

Question

we have the 6100 as a network printer in our office. one computer sees it fine and wil print to it, the other will install the drivers and recognise the printer as online, yet no program will print anything. nothing happens. when a test page is printed it works fine. i've tried installing as both a network printer and a local printer, the same happens for both. the laptops are identical, and the first suffered this problem also until suddenly it worke. the second was set up in the same way, but will not work.thanks