then delete a partition, you cannot install anything unless you delete one. you must decide what can be removed.
create an extended, which will be your final primary, make sure it fills the rest of your drive.
now can add more partitions, of the logical kind, within the extended.
when you say all the primary's have been changed, do you mean the hard drive is now dynamic? that is not good, linux is not compatible with it.
there is a way to change back to basic, but you risk wrecking Windows and your data. the official way is to remove everything from the hard drive, and then install Windows from fresh (probably from an installation disc). which is of course a lot of hassle.
EASEUS partition tool: