If you have the ugly screensavers back, then the hack has been uninstalled, so that hack isnt your problem. Did you download the correct Amazon bin file for the 2.5.2 update for your kindle? (US, I or DX DXI?) Did have have a font hack installed you have forgotten about? Did you download the Amazon 2.5.2 to the root of your kindle (ie not in a folder) AFTER you had updated the software to remove your hack? And then select 'update software' again?
Like I said, if you have the dead authors back then this hack is not your problem.