I install Unity 32 and can't have windows support builder ?

I install Unity 32 bit and i am 64bit pc ,
There is no any support installed with it ,
could I install or include windows build support within this unity or I must uninstall it and install it again .

When I build my scene this screen appear to me >?!

You need to specify that you want to build for Windows platforms when you run the Unity Download Assistant: