[CORed]

I would also add that you should only use accounts with administrator privileges when you really need to, e.g. for installing/uninstalling software, etc. Use a non-administrator account for you day-to-day computer usage, especially surfing the web or reading email. This limits the damage that malicious (or accidentally damaging) software can do. If you run some bad code under an administrator account, it has complete access to your files and hardware.