The "radio buttons" are the two circles on the left.
If you click one and then the other, the first one that you click on will be freed up. Or to put it another way if you click one after the other, the prior one will be deselected.
So the problem isn't with your or your computer. Probably.
It's most likely to be a bad download.
On the other hand, I see that you have
User Account Control active - see the little shield inside your icons?
It's a user rights thing, and it may be restricting you from making certain changes. And don't start in with "But I have full admin rights".
I used to install security software on universities and military bases, and I heard that all the time. Trust me.
You could turn it off, but first try the free program -
SimAccess.