Opening a message is highly unlikely to allow any infection.

Can you not right-click the message then select Delete from the pop-up context menu?

DoreneB said

logged in today and had a message pop up in a foreign language for the first time with a 2002 creation date...tried to just delete and not open, but system says I still have one unread message. I just want to get rid of it without opening or possibly infecting my computer

I did attempt to delete the message, but my inbox still shows I have one unread message-yet it is no longer displayed in the inbox where messages have been read. If I choose filters, I can pull it up again under unread messages-it just freaks me out that it's here at all