As described here:
The promlem has been fixed after HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5\SP was set to 1.
More info here too (linked in the page above):
Also could you check the following two registry keys and let me know what the values are?
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\NET Framework Setup\NDP\v3.5\SP
And
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\NET Framework Setup\NDP\v3.5\SP
To get pass the install error, if the value of the registry is 0, set it to 1.