The exact wording of the system errors you get would be very helpful in diagnosing this.
The AMD website selection fields for your card are:
Select the type of system that you have: Desktop Graphics
Select the product family your product belongs to: Radeon HD Series
Select your product: Radeon HD 7XXX Series PCIe
Select the supported operating system that you have: Windows 7 - 64 bit
This should get you to the download link for the AMD Catalyst Package from 4/25/2014
This installer will install their latest driver.