JACKSONVILLE, Fla. -- Joy Mills said she is extremely careful when using her computer.

Despite changing her account passwords every few months and never doing business with unsecure Web sites, someone broke through her defenses.

She found out after she couldn't log into her Yahoo account.

"I got an e-mail on my business account saying that my password had been changed and my account had been canceled," Mills said.

Mills knew something was wrong, and soon learned that someone had hacked into her accounts and starting changing her passwords.

"I was a little spooked, because I do a lot on eBay," Mills told Channel 4's Casey Black. "Then I realized that that password had been changed, too."

Mills searched eBay for her user ID and found that someone was bidding on PlayStations under her name and trying to pay for them with her money.

"So I e-mailed the sellers of all of the merchandise and said, 'Someone has hijacked my account. Do not take bidding from this account,'" Mills said.

But it was too late for one eBay seller. Thinking that Mills bid was legitimate, a seller in Denver paid $70 to ship the PlayStation to someone in Jakarta, Indonesia, who was using her name.

Computer experts told Mills that she was a victim of malicious spyware, which allowed someone to monitor every stroke she was making on her keyboard.

"Spyware is something that is put on your computer, typically without your knowledge," said Mike Anderson of Secure SI Inc.

Anderson said spyware appears in many forms on a computer, some of them annoying, some of them harmful.

"For instance, like a keylogger ... a program that would actually record your key sequences and then send them somewhere else," Anderson said.

That means the illicit program is recording everything, even account numbers and passwords.

"The scary part of all of this is that I do not know what else this person may not have gotten," Mills said.

Computer experts say spyware can get onto computers through following a link on an unscrupulous e-mail, or downloading something like a screensaver or chatroom tool from a Web site.

Even downloads of pop-up ads or unsolicited e-mails that claim they will remove spyware from a computer can actually download it.

Mills said she has filed a complaint with the Florida Department of Law Enforcement and the FBI.