Mark Nord, I did not modify any fonts. I merely tried to change the font by selecting a different one from the menu. A message came up saying the font change required a restart and that's when I got the reboot loop.
However I have now tried your suggestion of deleting that prsp.sh file and everything seems to be back to normal.
Ripplinger, I had already tried what worked for you but it was not successful for me.
Thanks so much to both of you for your responses.
Old wood best to burn, old wine to drink, old friends to trust, and old authors to read. Francis Bacon