What's a User to Do?
If you use a computer of any kind, anywhere, computer security not only affects you, it is your responsibility. If your device is compromised, you could be an unwitting partner in crime, or at least a source of inconvenience. And before you can even worry about computer abuse, you need to worry about power failures, natural disasters, making backups in case of a disk failure or virus attack, and making sure no one walks off with your equipment or backup media. If you work on a network, you have to observe network access and security regulations. You'll find that as quickly as manufacturers release cures for network or computer exploits, you will need to adopt them and incorporate them into your daily routine.
If your organization has installed a highly secure system, you may have to accept substantial restrictions on the administrative tasks you might have performed in the pastsheer torture for power users used to configuring their systems or at least their desktops to be just the way they want them. If your system supports mandatory access controls, you'll find that even if another user wants to let you read or print one of her files, the system may not let you.
Conversely, some organizations that really should know better sometimes display a stunning lack of security. In this case, you're on your own recognizance: sure, you could reprogram the boss's spreadsheet and plot yourself a big raise, but you would not want to be you the day you are caught.
Computer security is a multibillion dollar industry that addresses a threat that now impacts everyone. Major software companies warn users to install personal firewall software on their PCs in addition to performing frequent software updates to avoid the latest hazards. These days, only a fool or one uninformed would go too long without periodically updating his virus definition tables.