to share files your going to need samba..
sudo apt-get install samba
should do the trick, from there check out the samba userguides on how to configure it and more importantly how to use it. If you have specific problems with that, then post logs/errors etc
but in order for samba to work, you need to make sure your PCs can both see each other
Can you post the IP addresses of each machine?
in the linux command prompt type ifconfig
, and in the windows command prompt type ipconfig /all
Let us know the outcomes