If you are receiving emails with attachments that will not open do you have a virus?

This is more likely a case of someone else having a virus and your email address is on their computer. There have been several viruses that send themselves to all the email addresses in the infected computer's address book. Some of the latest ones do not show the originator as the "from" address, but randomly pick another address found on the infected computer. A good virus detection program like McAfee or Norton will catch these emails and quarantine or remove them.