PDF file problems solved
I have discovered that most of my problems in loading PDF files were due to my own impatience. When a PDF file did not appear after a few seconds, I started hitting the refresh button impatiently, and that caused really big problems, often causing my computer to freeze up completely.
I now find that with a slow dial-up connection it sometimes takes a minute or more to load a PDF file. I also found that trying to do other things while waiting for a PDF file to load also causes problems.
Also, often a recently used PDF file will reappear instantly.
PDF files have their advantages and disadvantages. The advantages are: (1) nice built-in word-search and word-counting features; (2) page numbering, which is often absent in HTML files; and (3) a PDF file often shows details of an original document that are not shown in HTML files and is sometimes virtually a photocopy of the original document. The disadvantages are: (1) the text cannot be copied and pasted by normal means, and (2) very slow loading with a dial-up connection (as discussed above).