Published: Oct 13, 2013 6:37 PM EDT
Updated: Oct 13, 2013 7:44 PM EDT

FORT MYERS, Fla. -- What starts as a normal day in the cyber world suddenly turns into a frightening experience.

Cryptolocker is a nasty ransomware that has infected millions of computers globally.

A red pop-up ad claims says your personal files are now encrypted. If you want them unlocked, pay $300. And the clock is ticking.

In July, WINK News Call For Action showed you a similar scam, the FBI ransomware. That malware similarly claimed you needed to pay $300.

"Giving (the scammers) money to take the virus off isn't going to remove the virus," warns Jeff Marsh, owner of All Star Tech Support.

"It's designed to keep extorting money from you."

How do you get rid of it?

"Take it to someone you trust, take it to someone you know is not going to gouge you, that's going to be fair and remove the virus," Marsh said.

Your best defense is to keep your anti-virus software updated. Though even that isn't guaranteed to work.

Experts advise you to back up your personal files in case your computer is ever compromised.