Published: Apr 22, 2010 10:27 PM EDT

FORT MYERS, Fla. - Computer systems worldwide locked up because of a software glitch. The Lee County Sheriff's Office was one of hundreds of agencies shut down and they had to go back to old-fashioned pen and paper.

One after another, Sheriff's Office employees dropped off or picked up their computers.

"It pretty much made the computer think itself was infected, so it deleted a lot of windows system files," said Network Administrator Adam bach.

Bach had the task of going through 900 toughbook computers, 850 desktops and 300 other laptops to fix the problem - a bad McAfee anti-virus software update.

"So, they were completely down," said Bach.

The 911 center lost computers on Wednesday from 10:30a.m. to 6:00p.m.

"We have cards that we write down the information from our calls, and we still had our radios thankfully," said Communications Trainer Chris Hodges.

Operators used a card system. Each terminal is assigned a district and each call goes on a card. Runners then physically take the cards to appropriate dispatchers.

Hodges says as reliant as operators are on computers, they are trained to function without them.

"We know we're going to be without our computers, in some instances, we're going to be without our radios, but we do have a backup plan for basically everything," said Hodges.

Mcafee said in a press release, "We believe that this incident has impacted less than one half of one percent of our enterprise accounts globally and a fraction of that within the consumer base-home users."

Bach says the computer issue should be fixed by the end of the week.

Mcafee says it can not tell how many computers were affected. But based on online postings, the number was in the thousands and maybe hundreds of thousands. In Rhode Island, five-hospitals were impacted and forced to send patients elsewhere.