I can’t open email attachments
If you have ever encountered an attachment that you couldn’t open, it was probably because you didn’t have the software necessary to view the file.
The usual suspect is the .pdf file, for which you can download a free PDF reader. If your problem involves a different file format, a quick search on the attachment’s file extension (the three letters after the period in the filename) should tell you what type of program you need. If the attachment lacks a file extension (which might happen if it was renamed), adding it back should set things right.