This is not Sharepoint but always find myself googleing for the command...
In Windows 8 if you goto add windows components there is a error...Dont know when this is going to be fixed.
What you do:
Insert win 8 dvd.
Open command prompt(i open as Admin)
Run this command:
DISM /Online /Enable-Feature /FeatureName:NetFx3 /All /LimitAccess /Source:d:\sources\sxs
Make sure you change the path of the cd rom to the correct one.
And now it should be installed