When I am trying to download attachments from my e-mails (even ones that I have sent to myself) I receive the following message on a toolbar that appears at the top of the page:-

"To help protect your security, Internet Explorer has blocked this website from displaying content with security certificate errors. Click here for options..."

However, when I click on "Display Blocked Content", nothing happens and I am still unable to open the attachments.

When I click to view the attachments (PDFs, Word documents, etc) online this works, but then when I try to download it, I receive the following message:-

"There is a problem with this website's security certificate.
  
 The security certificate presented by this website was issued for a different website's address.

Security certificate problems may indicate an attempt to fool you or intercept any data you send to the server. 
  We recommend that you close this webpage and do not continue to this website. 
  Click here to close this webpage. 
  Continue to this website (not recommended). 
     More information"

As everyone else that I have spoken with does not seem to be experiencing this problem, it is possible that my Outlook account has a virus. I have also had other people check their Outlook accounts on my laptop and they can open attachments perfectly fine.