SHERMAN, TX -- It's the time of year when many people use shipping companies to send gifts to loved ones; now, a computer virus disguised as an email is targeting customers who ship those Christmas presents.

Other than causing frustration and anxiety, computer viruses aren't a danger to your health, but they can put a dent in your wallet.
Some experts estimate that malicious software costs Americans hundreds of millions of dollars every year.

"Viruses and software removal are about 98% of the work that we do at the Geek Squad," said Roland Mahaffey, the Geek Squad manager at the Best Buy in Sherman.

He says the fastest way to damage your computer is to pick up a virus on the internet.
Right now, a computer virus--first identified a few years ago--is making a comeback.

A user receives an e-mail that appears to be from UPS or FedEx, stating that a package you have sent can’t be delivered, and prompts the user to click on an attachment to print out an invoice.
Those who do click on the attachment will be opening the door to a virus.

"You are probably going to be getting a nice little treat in your computer after that," said Mahaffey.

Besides just slowing down your computer, viruses can cause real damage including total system failure.

Sunjay Bustamante says she has had issues with her computer in the past, so now she follows some strict guidelines when she accesses her email.

"If I don't know who it is from I erase it I don't even bother opening it up," said Bustamante.

The Guys at the Geek squad say that isn't a bad strategy.

"I would definitely not open it, if you don't know who it is from or you haven't sent a package, I just wouldn't mess with it," said Mahaffey.

If you have sent a package and you get an e-mail, experts say the best thing to do is to confirm the information by visiting the delivery company's website, or by making a phone call, but avoid opening any attachments in the e-mail.