Laptop cannot access the main pc?!

Hello there, I have just installed a wireless network for a laptop running
windows xp home and for a computer which is running windows xp pro, both have
all the latest updates. They are networked up through a wireless router which
is running on the ip address of 10.0.0.2, the laptop is on 10.0.0.11 and the
computer is on 10.0.0.14. They both can connect to internet with no problems,
but when i share documents between them, from the laptop i can't seem to
access the shared documents on the computer, but the computer has no problem
accessing the laptop. The network is fully functional i have tested it out
with an networked game of couter strike with no problems. In theory there
shouldn't be any problems accessing each other.

Anyway my question is that is there any built in security measures in
windows xp pro to stop anyone connecting to it??

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