Signs That a Computer Has a Virus

Although it is easy to tell when your computer has had a virus for some time, catching one early on requires some diligence. Even small changes in your computer's speed or normal functionality could signal the presence of a virus. While some viruses result in an immediate crash, most viruses implant themselves slowly, and their effects can last for months, which is why early detection is key.

Time Frame

1. It can only take a matter of minutes for your computer to become infected with a virus, but the time you have until the virus renders your computer completely inoperable can vary. Typically, it will take about 6 months for an unchecked worm virus to completely shut down a computer. However, you will probably start noticing effects of the virus within 3 to 6 weeks.

Processing Power

2. The first thing that is affected by a virus is your processor. Because viruses are independent entities that require the use of a processor, you will notice that other programs that normally run well with no incident will start to chug or will be slow to open. Video and video-game performance will also be affected by the virus' strain on the computer's processor.

Speed

3. Because the processor's power is being slowly eroded by the virus, the next thing you will notice that may indicate a virus is a loss in speed. Slower web page loads will be most immediate, but over time, programs as simple as word processors will be slower to respond to input.

Program Malfunction

4. Once the virus has progressed very far, different programs will begin to malfunction. Some programs will stop opening, and others will open but freeze or stop responding after a few minutes of use. Programs will freeze, close unexpectedly or even fail to launch as a result of a virus. If you notice these phenomena, the virus in your computer has likely progressed to a point where it is beyond repair, and you will have to reformat your hard disk to get rid of it.

Prevention

5. Although the effects of computer viruses are far-reaching, they can be prevented. Simply installing and running an anti-virus program at regular intervals, as well as using a firewall program, should be enough to keep most viruses away. See the Resources section for links to free anti-virus and firewall programs. It is also helpful to stay away from websites you are unfamiliar with or that you don't trust.