webadept-ga has given me a good way to covert a pdf file to text.
Could he or somebody else suggest a way how other files that cannot be
highlighted can be converted to text? Those other files I am asking
about are document word pad, united paint, the list of url files
displayed by internet explorer, the list of files in webmail and if
there is anything else.

Have you tried saving the Wordpad file as a "text document"? This works for me.

A more cumbersome way would be to capture images of your screen by
pressing "Alt + Print Screen" then pasting the contents into a image
program then using a program that can extract text from scanned
images... Like I said, a little cumbersome but should work...

Provided the file contains *text* (so not a bitmap or other image) and
you can print it, install a "text printer" driver on your system and
set its output to File. You can then 'print' the file to the text
print driver and it will save the output as a text file.

Owain