error 0x4001100200001005 if problems persists contact Dell support

Finally I solved this problem and for anyone having similar issues i am sharing the solution

The problem in my case is that my backup DVDs got corrupted ( I don't know how ) and hence the error  0x4001100200001005 is coming up

Now the problem is How to restore an OEM ( preinstalled ) windows if you lose both HDD and backup

First of all remember that the preinstalled Windows on your system comes with a key. If you don't have a Physical backup of key don't worry your System Bios will have the embedded key in them. So even if you lose your HDD you can still retrieve your key from any software like Show Key Plus.

Here are the steps to reinstall a OEM windows 

1.Retrieve your windows key by any software ( R/W everything or Show key plus etc. )

2. Also note down the version of your original windows like Home, Professional, Enterprise, Single language  or whatever. This is critical to know the exact version of your windows otherwise the key won't work.

3. Now download the same version of windows from anywhere ( like getintopc.com )

4. Take it in any external drive mount the ISO file and run the setup

5. Now here is a trick - When windows prompt you for a Key Don't enter your OEM key because it will simply reject it by saying that it is not the correct key for this version of windows ( I don't know why ?)

Instead of your key use Windows Generic Keys to complete the installation.

6 Now it's all done once your windows is installed you can go to computer > properties and activate windows by connecting to an internet connection (easiest way) and if you don't have internet try phone activation ( use your retrieved key while activating and not the generic key ).

That's all 

Hope It will help someone. :)