Some undergraduates in a college senior design project mentored by Microsoft started developing a long overdue replacement. It was released independently on "Paint.net". It has bundles of features and a wide range of free add-ins with active forum help.
This product is not strictly free ware as the developers will accept donations. As a programmer and a user, if you make some money out of their efforts, why not donate a percentage?
In addition there is GIMP which is a free ware product. It is very comprehensive if not a little daunting at first. Probably the best way to learn GIMP is to open a Google page and type in "GIMP" plus what ever you want to do. There are some good help pages out there for GIMP. Download the installer here. When you try to download it your antivirus software may give a warning about the download site. Whist the warning is (possibly) to a degree true, it does not apply to this particular software. The site that you download this software from is home to many, many application downloads.
For a (not so) basic vector graphics package Serif Draw Plus SE is a very respectable package. There is a very low cost paid for edition as well.