MADISON, Wis. -- Experts say that viruses and spyware have cost computer owners an estimated $7.8 billion over the past two years.

But the right software can effectively protect against these problems. Consumer Reports recently finished testing some of the latest antivirus and spyware software programs and they ranked the results.

Consumer Reports created 5,500 computer viruses to test the effectiveness of antivirus software. The viruses were quarantined on a CD to maintain tight security during testing.

"That computer was never connected to any other computer or the Internet. And we worked in a virtual environment, which was erased immediately after testing," said Dean Gallea with Consumer Reports.

Consumer Reports tested a dozen antivirus programs to see if they could detect and block new viruses. Testers said they found a big difference in detection rates.

"Some products did really well detecting the viruses just by scanning them. Other products had to wait until the viruses activated. And some couldn't do well at either," Gallea said.

On another computer, Consumer Reports tested 12 software programs designed to protect against spy ware, which can also harm a computer.

Gallea loaded a computer with programs that simulate 17 different kinds of spyware. Gallea found that no one program could eliminate all the spyware -- but some proved better than others.

In the end, Consumer Reports said a good choice is ZoneAlarm Internet Security Suite for $70. It offers good protection against both viruses and spyware, Consumer Reports testers said.

In addition, testers recommend a free spyware program from spybot.info called Spybot Search and Destroy to give you added protection against spyware.

Experts said that spending money on software that continuously checks a computer is a good idea, but there are also several free options available.

For more information, visit Consumer Reports.