T420 Drivers Issue

So I have a friend who really needs a laptop, so I purchased a t420 off Ebay with 8gb RAM for a hundred dollars and a 128 gb SSD to replace the old HDD it came with.

The laptop came with an OEM copy of Windows 7 pro, which I managed to transfer over when I installed Windows 7 on the new SSD, but now I've ran into problems.

I have no drivers, and no ability to connect to the internet to download drivers. Not even Ethernet is working because I somehow lack the Network drivers to make that happen. So I'm going to have to port over the drivers from a USB, question is how and where to do I find the appropriate Drivers?