Im not a pc genius but i have been searching for weeks on a easy way to share files with anyone sharing a modem with wi fi or wireless capabilities.
ill break it down to a simple and easy way for newbies and explain which setup im talking about.

OK lets say you have a pc and your pc is connected to the modem with a ethernet cable (alot like a telephone calbe but bigger, usually yellow or blue cable)

now lets say you have a laptop that is in another room with one of these things:

a) some kinds of built in wireless detection (my laptop has a switch that turns on the wireless and shows a orange light) or
b) a wireless card that u plug in by USB or other

right so we have these easy things now and understand how there connected
so what we need to do next is make sure of a few things.

now is your laptop connected to the internet
yes? if so i assume its connected to the same network as your pc but ur wireless so this is good.

ok so lets move onto actually sharing files.
this part is sooooo easy if explained simply so ill do my best.

now u will need both ur pc and laptop close by to make it happen.

1st thing you need to do is this:
find the folder you would like to share with your laptop lets say its the folder named "music".

ON YOUR PC

1. right click on that folder and click properties
2. go to tab titled "sharing"
3. check the box "share this folder on the network
4. type in ANY name for the folder lets say: MUSICPC
5. IF YOU WANT TO BE ABLE TO EDIT THE FOLDER FROM THE LAPTOP CHECK THE BOX BELOW TITLED "allow network user to change my files"
6. click ok and that part is done.

i need you to do a few things now before we go to your laptop

goto to your desktop and click "start" \ control panel \ network connections
in network connection go to the tab at the top of the page titled "ADVANCED" and click on "network identification..."

go get a pen and paper and right down exaclty what your computer is called its under "FULL COMPUTER NAME:" and the name of your file that you wanted to share so in this example were using: MUSICPC

MAKE SURE YOU WRITE DOWN THE "FULL COMPUTER NAME" NOT "COMPUTER DESCRIPTION"
now close it all and quickly restart your pc and go grab your laptop

ON YOUR LAPTOP

this part is quite easy as long as you have followed the steps above you should be right. the only thing you might come across here is easy fixed but ill explain it all.
now go to your laptop and open a internet page.
in the address bar type this EXACLTY

\\(your computer name that i told you to write down)\(folder your sharing)
then press enter
so it should look like this for example
\\irish\musicpc

if you have used all the right names it will show you the folder you want to see thats on your pc.

LAST STEP
just go up folder (picture of folder with green arrow pointing up) and it should take a few seconds then show the exact folder your looking to accsess named "MUSICPC" for example.

right click on the folder go down and "CREATE SHORTCUT"
you will then see a box saying "cant create short cut here move to the desktop insted" click yes then close any open folders.

YOUR ALL DONE
on your laptop DESKTOP you should have a folder with little black tubes underneath it.
to do the same process from your laptop to pc just follow the same steps but start on your laptop.

IF YOU SEE THIS ITS YOU HAVE COMPLETED YOUR SETUP

enjoy sharing guys i hope this helps i wished i found this somewhere on the internet before i had all this hassle

IRISH!