How to Enable/Install Dot Net framework 3.5 on Windows 8 Without Connecting Internet.

Step 1: Insert the Windows 8 disc.
Step 2: Run Command Prompt (cmd) as Administrator.
Step 3: Now, just copy and paste the below code (the G on Blue  color is your Disc Drive letter, replace it with your disc drive letter) on command prompt and hit 'enter'       

dism.exe /online /enable-feature /featurename:NetFX3 /Source:G:\sources\sxs /LimitAccess

Step 4: When its successfully done, restart your PC and enjoy!