1) Put both computer in the same workgroup
2) Check to see if file and print is installed on both computer network properties, check to see if NetBIOS is enable in advanced setting on both computer network properties.
3) Disable firewall for the moment on both computer
4) Restart both computer.
5) Now go into command prompt on each machine and ping the other. Verify you get replies from the other machine before proceeding.
6)Create a folder, don't create it in "My Document" sometime you can't share in this folder. Create the folder on your desktop or somewhere else, add the files you want to share. Right click on the folder and select sharing and security, go to the share tab, at the bottom click that blue link that says "If you understand the security risk...and so on" afterward a box will appear, just select "Just enable file sharing"
7)Do step 6 for any folder you like to share on both computer.