If this is only happening with attachments that are PDF files, then you need an application that recognises and can open PDF files.
PDF is Adobe's format for documents that can be transported/transferred without the risk of the document being changed. Adobe has it's own PDF Reader which you can download and install.
You may already have a PDF reader installed on your system, so try this. Instead of attempting to open the attachments direct from the email, right click the attachment, then save it to your Desktop. Then double click it from there after you have virus checked it. If it still will not open, then you need the Adobe PDF reader.
I have xp word, outlook express dell computer When I try to open an attachment in Outlook Express or download anything online (bank statements), I get this message
C: Documents & Settings (my name)\Local Settings\Temporary Intgernet Files\Content IES\KVQ5YCQL\ FESt. Sing.POST 1011180001.pdf is not a valid WIN 32 application. What do I need to do to be able to open attachments as well as other information on line I keep getting this ***** PDF is not a valid WIN32 application. Obviously I am missing something on my computer. Thank you in advance for your help.