xampp - Visit Site - Download
Now install xampp to your computer. The usual install location is C:\program files\xampp. You will be asked if you would like to install any of the components as services somewhere during setup in a pop-up. i'd recommend you say no otherwise your computer gets all the stuff starting when you Log into windows.


Then go to the place you installed xampp (the default is C:\program files\xampp) and enter the folder called htdocs. Delete all the files in here.
Create the Folders you will want, for example Music and Pictures. If you know how, maybe create a simple html site and drop it in htdocs too, that way you could have a friendly interface for your File Server!

Now go to Start > All Programs > apachefriends > CONTROL XAMPP SERVER PANEL and then press start next to Apache and MySql.
To see your new file server go to internet explorer and type the name of your computer/Lan IP address in the URL box and go. You should see something like below.

If you created a friendly html site, it may look like the one below


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If you already had xampp installed, create a new directory inside htdocs and then when you need to access it you go to Your computers name/Lan IP address followed by the name of the folder.
For example for me http:\\amd\fileserver\