The Madison County School District is one of millions of entities, businesses and individuals in the U.S. that are affected by the April 8 "death" of Microsoft Windows XP.

On that date, the software company said they will no longer make security patches and updates, leaving computers running that software susceptible to a multitude of viruses and malware.

Gavin Guynes, director of technology with the MCSD, said they have been constantly replacing aging machines for the last 3-4 years but will still have around 1,200 computers running Windows XP on April 8.

"As they die, we're replacing and putting new machines out there with Windows 7 and Windows 8," he said. "From a support standpoint, we will still have antivirus software on them. (The antivirus companies) have told us they'll continue to support Windows XP."

The MCSD owns approximately 4,500 computers, and there are anywhere from 2,500-3,000 devices that connect to their network on a daily basis.

Since the computers run on a network, Guynes admitted there were concerns about the possibility of viruses making their way into the system.

"Any time software is not supported like that, they're always susceptible to viruses and back doors," he said. "It concerns me. Every workstation we have is connected to the Internet. Every PC in this network is then susceptible."

Each workstation costs the district approximately $865.

Others are in the same boat as the MCSD and the impending "death" date.

According to David Chou, chief information officer for the University Medical Center, they have upgraded approximately 2,500 of their 4,500 computers.

"We are going through the steps to upgrade as we speak and this is a priority for my department," he said.

Computers are used for different functions at UMC, with some units once connected to MRI machines.

Banks are feeling the brunt, too, since it's estimated that 95 percent of ATMs still operate by Windows XP.

Richard Carlisle, owner of Madison Computer Center in Madison, estimates that one-third of the PCs in the world still operate Windows XP. He said the threats are real.

"Viruses, malware, adware, ransom ware, worms, Trojans, keystroke-loggers and anything else written to hack, infect, snoop or steal from users on Windows XP on or after April 8 will soon live without fear of a patch from Microsoft."

Carlisle said the effects won't be felt immediately for XP users browsing the Internet, but down the road they won't even be able to connect.

"Computers will not cease to connect overnight, but over time virus writers will find more and more vulnerabilities and ways to infect the system," he explained. "With no security updates the risk of acquiring a virus will increase every day.

He added, "When machines become badly or repeatedly infected, most Internet service providers will block the machines to the Internet in order to protect their own systems as well as to prevent the spread of malware."

Carlisle said the sooner people replace their machines, the better. Also, he said it's a good time for people interested in switching from PC's to Macs.

"Replacing the computer entirely or upgrading the machine where possible is the only realistic option other than discontinuing the use of a computer," he said.

Apple recently announced it would be ending support services for its Snow Leopard operating system.

Carlisle said these are just ways to force people to upgrade or buy new machines.

"Microsoft considers XP to be obsolete and this is their way of forcing users to transition to a more modern operating system."