Don't open email attachments unless you are 100% certain that it is genuine
Part of our business is involved with virus removal.
This week things have gone ballistic with infected machines. Most of the problems have been caused by users opening email attachments. Unless you are absolutely 100% confident in the validity of the attachment, delete it straight away.
Banks don't send attachments.
HMRC don't issue refunds (Well very rarely and they would advise you by Royal Mail)
If you haven't ordered anything you don't have a parcel to collect.
You have no long lost relatives living in Nigeria to leave you a million pound fortune.