I can identify my files on WD by mere size of the files but cannot open them. How do I go about opening my files since they are different. Some are excel, others, word and powerpoint?

Secondly, my e-mails are read only. I can not do anything like download them back onto my computer and use content e.g attachments.

Your question is unclear.

Please post details what caused you to be in this situation and what you expect to accomplish. It would be helpful to specify file paths, applications you use to accomplish tasks and so on.