My 12.04 install has become slow and balky. I have downloaded the latest 12.04.2 ISO file to reinstall, but I can't get md5sum to check it. When I follow the instructions in "How to md5sum" I get nothing but error messages.

Can someone give me a (preferably graphical) method to verify the ISO file? I''m no good at typing long entries into the command line, so a click by click would be good. Thank you.

Jim