Direct X installation error

I like to play steam games such as civ 5 and garry's mod but i no longer can do this. I have a new 13 inch mac book pro about a month old. II played a few games on windows when i got it then i guess an update came out for direct x and i try to install it but it gives mean error saying"An Internal system error occurred please refer to DXError.log and Directx.log in your Windows folder to determine the problem." So i checked and apparently i do not have a signed version and i keep installing direct x from windows website and it keeps saying the same thing. Can anyone please help?