I want to know how to setup the laptop so it can share and get files from my desktop.. I know you have to set directories to share but I can't remember how to do the whole thing.
Thanks
Marv

Look Up File and Print Sharing in Windows Help. I'm assuming you have a LAN with both PCs connected to it. The Help will tell you what you need to do.

The main computer is plugged into cable.. you are in long island so you probably also have cablevison. The laptop has a wireless card... so now what do I do

Do you have a wireless router? Doesn't sound like it if the main PC is plugged directly into your cable modem. You need to get a wireless router.

Another option is for you to get a usb wireless adapter , plug it in to you desktop and create a wireless ad hoc network between the desktop and the laptop which can then share an internet connection and share files. A usb wireless adapter cost less than 40 dollars and its not that difficult to set up the ad hoc network.

RadioShack sell a crossover USB cable under their Gigaware Brand than can directly connect two XP/Vista PCs and lets you move files back and forth (about 30 dollars I think).
Note. You can't use a normaal usb cable as you'll damage your motherbord.