You need the drivers for the laptop, go to the manufacturers site, find the support section and download the drivers. If you can’t then you are off to google the wireless chip and get a driver
This is the solution – no other way around it. The manufacturer should have a download page where you can download and unzip all the drivers relating to your laptop.
As already said, you’ll need to do it on another machine, and maybe burn a CD containing all the files (providing both machines have an optical drive).
Networking drivers are very specific to hardware. You may find that there are multiple networking drivers for different networking devices that your machine may have had installed at the time it was built. Download them all!
That being said, in its most basic form, a simple USB stick with files on it should work without drivers on most machines using windows 7. Does a USB stick work ? You’ve not specifically said whether it does or doesn’t.