What version of Adobe Reader do you have? Don't confuse Acrobat and Reader. Update to Adobe Reader 9 - it won't affect Acrobat. Then make sure you always open .pdf files with Reader (via Folder Options).
As I said, I have Acrobat Pro v6 and Acrobat Reader v.9 installed. Until recently the Acrobat Pro has remained in the background except when used to convert files to PDF for publication or commecial printer.
When merely opening a PDF file, Acrobat Reader has opened and no conflicts.
Now, possibly since upgrading to v.9, the old Acrobat Pro has beaten Reader to it!
I also have tried the Windows procedure - "Always use this program to open this type of file" and selected Reader v.9 to do it. No change.
My laptop doesn't have Acrobat Pro loaded and I can open the web site download so there's nothing wrong with the website itself.
Thanks but Reader in folder options does show version 9.3
The old "full strength" Acro Pro v.6 is probably now so old that it wont answer to the bells and whistles of later generations.
Your clear screen shot shows PDX and PDFX which are presumably recent twiddles and improvements?
There are freebies or inexpensive apps which will convert various formats to PDF, I'm thinking that is my best way forward. Probably Word.doc and .jpg will be alright, but I must have a Corel.CDR conversion facility.