If the question is whether the router performs its functions (as others wrote it should work this way), then the easiest way to find out is:
ping <ip address>
and try to mutually ping the computers from each other. If the ping goes, and the shared folders are not visible or somehow work incorrectly, this is definitely a question not in the router, but in the OS settings.
In the settings of the balls, I know for sure that there is some incompatibility between XP and 7, so google to help, do not forget about firewalls, firewalls, antiviruses that can interfere with the work of the ball.