shankhan,
Since I don't see Windows 8 drivers for this system, try the Windows 7 64-bit drivers in the Windows 7 Compatibility mode
When you reinstalled the operating system, did you install the Dell System Software(if applicable) and the chipset drivers first? If not, the rest of the drivers will fail to install. How to Download and Install Drivers in the Correct Order
Start with the Dell System Software and the chipset drivers and follow the list.
Rick