Now-a-days almost all 3rd party software require
Microsoft .NET Framework  installed in your system. The required .NET Framework version might be 
different for different software and the most required .NET Framework 
version is 
3.5 which comes preinstalled in Windows 7.
If you are using Windows 8 , you might face a problem while trying to run a program which requires .NET Framework 3.5 version Windows 8 
doesn't come with .NET Framework 3.5 version. It comes with the latest .NET Framework 4.5 version preinstalled.
Whenever you try to open a program requiring .NET Framework 3.5, you get following message:
An app on your PC needs the following Windows feature:
.NET Framework 3.5 (includes .NET 2.0 and 3.0)

There are 2 buttons given to install the .NET Framework version or to
 skip the installation. If you decide to install it, Windows tries to 
connect to Internet to download the setup files of .NET Framework 3.5.
That's strange because Windows 8 setup contains .NET Framework 3.5 
setup files but still Windows tries to connect to Internet. It would 
have been better and easier if Windows 8 installed the .NET Framework 
3.5 without Internet connection just like it does for other 
Components 
 such as Media Center, Internet Explorer, etc which can be installed or 
uninstalled using "Programs and Features" applet in Control Panel.
If you don't have an Internet connection or if you don't want to 
waste time and bandwidth in downloading the setup files, here is a way 
to 
install .NET Framework 3.5 offline in Windows 8.
Today in this tutorial, we'll tell you how to install .NET Framework 
3.5 in Windows 8 without any need of Internet connection. You can 
install it offline with the help of a single command. This method 
requires Windows 8 setup disc or ISO file so make sure you have Windows 8Setup Files   with you.
So without wasting time lets start the tutorial:
.
1. First you'll need to copy Windows 8 setup files 
to your hard disk. If you have Windows 8 setup ISO copied in your 
system, you can mount it by right-click on it and select "Mount" option 
or you can extract its content using  7zip
If you have Windows 8 setup disc and don't want to copy its content, 
its ok. Just insert the disc in your CD/DVD drive so that Windows can 
access its content.
2. Now open 
Command Prompt as Administrator as mentioned here 
 and then provide following command
Dism /online /enable-feature /featurename:NetFx3 /All /Source:F:\sources\sxs /LimitAccess 
Here "F:" represents the CD/DVD drive letter in your system which 
contains Windows 8 setup disc. Replace it with the correct drive letter 
according to your system.
If you extracted Windows 8 setup files in a directory, replace F:\sources\sxs with the correct path.
3. As soon as you execute the above mentioned 
command, Windows will start installing .NET Framework 3.5 in your system
 and it'll not require Internet connection.
 
It'll take a few minutes and you'll get a message that the operation completed successfully.
4. That's it. Now you have installed .NET Framework 3.5 in Windows 8 without using Internet connection.
 Thankyou