What are ways a computer can become infected on the internet?

There are a few ways evil can find its way onto your computer. The most common way is opening attachments that supposedly came from your friend. Spyware and viruses can sometimes send messages with copies of the virus from your friend to everyone in their address book, pretending to be your friend. Rule of thumb: never open any attachment from any email that you didn't expect. Another way your computer can get infected is if you download a rogue file on the internet. Always check to see if what you're downloading comes from a reliable source. If in doubt, have an anti-virus program scan the file before you run it. The most malicious virus is a Trojan Horse program, a term used to describe a virus that pretends it does one thing, while it really messes up your computer. Be very cautious what you download and always scan what you download. Some websites Phish other websites (pretend to be the true website), but phishing checkers are available on the internet. If you download a file that has an extension (such as .jpg or .doc) that you are not familiar with, immediately delete the file and double check the website to make sure that you're downloading something safe. Some programs freely admit to being spyware to prevent lawsuits (usually on paragraph 56 of the 57-paragraph license agreement). Bottom line: be sure of what you download and always scan it before you run it. Next, never start your computer with a floppy disk in the floppy disk drive. Not even that "game" (wink-wink) Bob slipped you last week. Your computer is most vulnerable as it starts up. As part of your start-up routine, eject any and all floppy disks. Finally, some evildoers can get into your network, destroy and vandalize, slip in some viruses, and run away unnoticed. This is only true if your router has any wireless capability. To counteract this, watch your Windows for any masked men crouching by your house with a laptop in hand. Better yet, be sure to enable security for your router (usually go with WPA unless some hardware is incompatible) and create a strong, secure passWord. And don't get paranoid. 90% of what you download on the internet is safe, especially if the website you're using is either secure (look at the URL for https://) or is checked by third-party software (you'll usually see an ad somewhere on the page that says "Virus-Buster Protected!" or some other stupid slogan. Breathe a sigh of relief when you do.). Hope this answer helps!