Then you will need to determine what hardware came in that unit, find another unit or units with the same network adapters and download the drivers for those models. That model never came with anything other than Windows 8.1 installed from the factory so they do not provide drivers for other Windows versions. This is not uncommon and is the reason why downgrading isn't generally recommended. In some cases, there may not even BE drivers intended for use with prior operating systems available ANYWHERE, which IS common. Downgrades most often run into problems when it comes to finding the network adapter drivers than any other area.
Also fairly common is that those Windows 8.1 drivers WILL work with other versions of windows, so if you haven't at least tried them yet, I would. There's a good chance they'll work fine.
If you have access to an aftermarket USB wireless adapter that you also can get the drivers for, you can try temporarily using that to find and install the drivers through Windows update or in the control panel device manager applet manually.
They MIGHT work just fine. They might NOT work at all. Network drivers are fickle, not always working or being compatible between versions of Windows. I've seen at least 50 or more specific situations where a downgraded unit would NOT work with the Windows 8 drivers. And by the way, he's NOT looking for windows 8.1 drivers, he's looking for a Windows 7 driver. So this:
For windows 8.1 just use windows 7 drivers they should work just fine.
Cannot even be applied to this thread making it irrelevant. If you know where there are windows 7 drivers for a device that the hardware string does NOT have any older drivers for, by all means, post a link. That's what he's looking for anyhow.