You have to create the same user on the laptop and pc, with the same password (NOT a blank password, it won't work). If it is the Administrator account then you have to use the same password.
After that, disable the "Use simple file sharing": open a folder, then go to the menu Tools->Folder options->View and uncheck the last record, the "Use simple file sharing" (I assume you have Windows XP on both computers).
Next, see in which folder you saved the melodies. Right click on it, Share.
If you created a new user, you have to add the user in the tab Security, and the user need Read rights.
After that... You have to see what IPs your computers are using: start->run->cmd
and in the command prompt window type:
ipconfig /all
The same from the other computer
They should have some similar IP's, only the last number differing.
From the laptop:
start->run->//the_IP_of_the_desktop
and you should be able to find your share. More, you should be able to copy your files from PC.
PS. If you give to administrator account a password (highly recomended), don't forget it (highly unrecomended). I repeat, DO NOT FORGET THAT PASSWORD.