atul.optimist,

When you reinstalled the operating system, did you install the Desktop/Notebook system software 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 Desktop/Notebook system software and the chipset drivers and follow the list.

Rick

Hello,

I am currently having similar problems. Unfortunately, whenever I try to install the Dell System Software and restart my computer as prompted, the installation does not take into effect and I still cannot install any other drivers.

Any advice on where to go from here?

Use the WSUS Offline Update to fully patch Windows 7:

http://dellwindowsreinstallationguide.com/wsus-offline-update/

Then use the latest version of Dell System Software:

http://dellwindowsreinstallationguide.com/driver-sets/dell-system-software/