Thats because you have simple file sharing on.
Load up windows explorer:
Tools > Folder Options > View > go to the bottom and untick "Use simple file sharing"
Ok all that, go back to the folder you wanna share, right click it, go to the 'sharing' tab, click the permissions button then the 'add' button, add a user you want to grant permissions to, it needs to be a user on that laptop, one with a password aswell. give it full read/write permissions and ok all that.
Then from the other computer go start > run and type \\YOURCOMPUTERNAMEHERE\YOURSHARENAME here
replace those with the appropriate computer name (or ip address) and share name, if your computer is called pc1 and the folder your sharing is called files you would do:
\\pc1\files
you will be prompted for a username / password (hopefully) type it in, click ok and you should have the windows explorer window popup showing you the shared folder.
job done.