Have you removed the drivers before installing the new ones? To me it seems like a driver issue, but it's a Razer product anything could be wrong with it. If that fails try letting Windows find the driver for you, worked for me in some cases.
If you still can see if you can get another blackwidow (if you're under warranty) and sell it . Razer makes horrible products, but at least they know this and have good/decent support from what I hear.
Here are some reputable brands you should consider purchasing next time.
Ducky
WASD - Lets you customize your keyboard
Filco
Roosewill RK-9000 models - I've been told these are Filco rebrands