Windows 7: Sharing printer through mixed wired/wireless network

Hi all,
My printer is connected to computerA which is connected through ethernet to computerB which connects to a wireless network. The wireless network has an internet connection and also serves several laptops, unfortunately the laptops cannot "see" computerA on the network and consequently cannot use the shared printer, the internet connection is available the on all computers. The one laptop runs windowXP and everything else uses windows7. ComputerB has no trouble using the printer. Any help would be greatly appreciated!

Can you ping computerA from one of the laptops on the wireless connections.

The links below might help.
Sharing files and printers with different versions of Windows - Help & How-to - Microsoft Windows

http://windows.microsoft.com/en-US/w...ons-of-Windows

Stpbby: I can ping my laptop from my ComputerA, but not the other way round. I can ping computerB from the laptop, for now neglect the XP-Windows 7 thing at this stage as that's not really the main problem at this stage.