I"m no expert on the "hosts file" but this may be helpful:
If you want a Windows machine to recognize your Pi on your local area network by name, it needs somewhere local to find that name, instead of using some external DNS (domain name server) elsewhere on the network that won't know anything about your local system. On Unix/Linux systems it is a "hosts" file, often in /etc/hosts and in Windows XP it might be C:/WINDOWS/system32/drivers/etc/hosts
...and by the way if you have a working wireless configuration (USB WiFi adaptor?), I think several people would be curious about all the details on that; it seems to be tricky to get that working.