A computer can also come down with a virus ("computer virus"). This occurs when a program called a virus or malware sneak their way into your computer—either by you opening a malicious attachment from unknown emails or finding security breaches on your computer. The reason they are called viruses is that they tend to "change" and "adapt," attempting to avoid virus detection software.
And, like viruses in humans, these programs can cause a whole symphony of "symptoms." Some are harmless and irritating, while others can delete files or corrupt your computer. In either case, it causes your computer not to function as it should. The best way to protect against such “bugs” is to run an anti-virus application. These stop viruses in their tracks! But even anti-virus programs need to be updated regularly because, like viruses in people, computer viruses are always mutating. So, be careful what emails you open, and use an anti-virus program and you’ll keep the bugs out of your PC!