Chatdanger - how to keep SAFE while chatting online

"...The program (virus from the attachment she opened) enabled him to see when she was online and control her computer. He was able to control her mouse and her keyboard. He typed threatening messages and obscene words making it appear that SHE was typing them in the chatroom and then made her CD drawer start flipping in and out. She was terrified..."

(14 year-old girl)

Viruses can muck up your entire computer. They normally travel in attachments and can be common in emails and instant messenger. The best way of protecting yourself is by not opening attachments from people you don’t know. Also make sure you have up-to-date anti-virus software on your computer. This is not only to protect you from receiving viruses but also to stop your machine from passing viruses onto others by mistake.
If you receive nasty images, even rude pictures of your friends, on your phone or by email or whatever, don’t forward them. It is best to delete them. Depending on the picture you may be breaking the law just by forwarding it.
You should be careful about receiving pictures from people you don’t know. Also be suspicious of people who ask you for your picture, and never feel pressured or agree to sending a ‘naughty’ picture of yourself. You don’t know what they want it for or what they will do with it. It would make you very vulnerable – the person might post the picture on the internet and show other people, or they might even threaten to show this to your parents or carers, or teachers, your school friends, or even your girl or boyfriend.