I have 3 computers 1. Windows XP sp2 desktop,  2. Windows XP sp2 laptop  3.
windows XP sp2 desktop.  internet comes in to a cable modem which is
connected to a router, which is connected with an ethernet cable to computer
1.  Computers 2 & 3 are connected to the router wirelessly.  I recently tried
to setup a home network so that the 3 computers can share files, and my
printer which is connected to computer 1.  i was able to setup  computer 2 &
3 for file sharing, and computer 1 can view and open files on 2 & 3.  However
computers 2 & 3 cannot view or open files or access the printer on computer
1.   I have tried trouble shooters and checked all the settings it all looks
correct.  if there is anything i'm doing wrong i would appreciate the help.  
or could it be the way they are connected with 1 wired to a router and the
others wirelessly.  

Thanks in advance to any one who might be able to help i sincerely
appreciate it.

Josh