Can't access host computer files

I can't figure out why I can't access files on my host computer. Everything was fine until I fianally encrypted my router connection. I set everything up correctly on my wireless computer, and I'm able to log on to the internet and pull files from that computer, but I can't pull files from my host PC. I'm running windows XP SP2 with the firewall off on both PC's. I'm sure there's a simple permission I forgot to grant, but someone plaese help me figure out what it is.