Like the other poster said. Buy a router and follow the instructions which should essentially tell you to connect it to your cablecom modem and then either use your built in WLAN function on your laptop or insert the wireless dongle into your USB port on the PC and you're away. The only slightly sticky bit may come if/when you set up the security (i.e.password) but it isn't rocket science.

Have faith in your abilities and jump in!

(if you have any issues with the process just post more and someone will help - might even be me)