I ended up fixing this earlier today lol. I just downloaded the new version on a different computer and copied the files from there. I didn't even mean to delete the files in the first place either though. *~*
*sigh* I'm an idiot who broke my paint.net -_- I deleted my paint.net files before installing the 4.0.5 version and now when I try and install the new one I get the "there was a fatal error during installation (1603)" and, idk what to do... ;-;