Go to http://www.avg.com/us-en/homepage and download a free, excellent, anti-virus program. If you want the deluxe version, they'll sell you one as well...
Tom
Tell your credit card on online payment provider to chargeback the item...
Simply call the toll free number on the back of your card and report the unauthorized use of the card. They'll charge back that amount and give you a new card number...
delete the email and go back to sleep...
Call your bank and tell them to de-authorize the withdrawals...
at least call your bank and stop any further withdrawals...
Throw those letters away and go back to work...
buy another one, from a reputable company this time...