Error while compiling the project after import

Error: After import a new project from another server, while compiling system gives below error message:

AX1004: Reference System.Core, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089 was not a valid model assembly.
\C:\Windows\Microsoft.Net\assembly\GAC_MSIL\System.Core\v4.0_4.0.0.0__b77a5c561934e089\System.Core.dll

Warning Message:

MSB3644: The reference assemblies for framework ".NETFramework,Version=v4.0" were not found. To resolve this, install the SDK or Targeting Pack for this framework version or retarget your application to a version of the framework for which you have the SDK or
\C:\Windows\Microsoft.NET\Framework\v4.0.30319\Microsoft.Common.targets
Line: 983

Possible Reason:

It might be your .net version.

Solution:

Install .net version 4 from below link

http://www.microsoft.com/en-us/download/details.aspx?id=8279

After installing this update this error should not come.

-Harry