Error while installing SQL Server 2012 Enterprise edition

While installing SQL Server Enterprise edition, I came across the below error

Microsoft SQL Server 2012 Service Pack 1 Setup

The following error has occurred:

Error while enabling Windows feature : NetFx3, Error Code : -2146498298 , Please try enabling Windows feature : NetFx3 from Windows management tools and then run setup again.

Problem

.NET Framework 3.5 is not installed on the server

Failed steps

1. Go to server Manager -> Add Roles and Features - Installed .NET Framework 3.5 - Failed

2. Downloaded .NET Framework 3.5 from internet -> Go to server Manager -> Add Roles and Features - Installed .NET Framework 3.5 - Failed

3. Ran the below command in command prompt (Run as Administrator)

dism /online /enable-feature /featurename:NetFx3 /source:”location to file” - Failed

Deployment Image Servicing and Management tool

Version: 6.2.9200.16384

Image Version: 6.2.9200.16384

Enabling feature(s)

[==========================100.0%==========================]

Error: 50

The operation is complete but NetFx3 feature was not enabled.

A required parent feature may not be enabled. You can use the /enable-feature /a

ll option to automatically enable each parent feature from the following list. I

f the parent feature(s) are already enabled, refer to the log file for further d

iagnostics.

NetFx3ServerFeatures

The DISM log file can be found at C:\Windows\Logs\DISM\dism.log

Resolution

1. Insert Windows Server 2012 CD. 

2. Open Windows PowerShell (Run as administrator)

PS C:\Windows\system32> Add-WindowsFeature NET-Framework-Core -Source D:\sources\sxs

Success Restart Needed Exit Code      Feature Result

------- -------------- ---------      --------------

True    No             Success        {.NET Framework 3.5 (includes .NET 2.0 and...