wireless connection

Friends of mine tried to help me out and reboot my computer now I have lost my wireless connection I tried downloading from here and installing it on my Inspiron 600m but I still have nothing., Is it possible for me to purchase a wirelss card and install that on my computer so I can acess the internet or do I have to reinstall the drivers? Any help would be grateful. There is nothing in the taskbar telling about wiresless connections and they basically wiped everything off the computer.If I do have to download how do I know which things that I need to reinstall on the laptop I am not very good with computers thinking I should bring it somewhere else and have them look at it for me..unless it is easy and I can do it myself.

Thank you for any help