Unable to Ping other computers on Home Network

[irishmen9]

Hi everyone. I started to get my network at home finally set, the way I want it. I have FIOS and the router and software that it comes with. That is all I am running currently, but I have a Linksys WRT54G that I intend on making a WAP. The WAP is for increased wireless connectivity, and to hard wire my XBOX into. The FIOS router will be put in a seperate room in my Apartment where I have my desktop computer's, that way everything has connectivity, and I dont have 8000 feet of Cat5 running everywhere. This way I can also setup a domain and fileserver, for learning purposes. To my first question. I have been trying to ping the other laptops that I have in my house that are on, and I am unable to. I have made it so I can ping within the router, but I am unable to ping anything but the router from each of the machines. If I log into my router and attempt a ping from my router(built in feature) I am unable to ping the computer that I am trying to ping. Now I have connectivity on all my computer and I have no issues getting to the internet. I have turned off all firewalls, and anything that I could think of that would block incoming pings. I have to XP laptops and one 7. The other thing that I am trying to do is make it so I can access each computer from the background. For example at work I have the ability to go Start>Run and type in \\machinename\driveaccessing$ and I am able to access everything on that computer with no issues. I want to be able to do this for file transfer purposes, and also so I can manage my server once built remotely. If anyone has any insight or can give me a hand I would greatly appreciate it. Thanks in advance.