Security

General

Security on Computers covers a number of topics the main domestic and simple systems are covered by the three topics Firewall's, Anti virus and Passwords.
In fact more stringent forms of each can provide most of the security your likely to need adding to which are permissions which is beyond the scope of a simple explanation.

Firewall

Visit the firewall page for more detail but in short the firewall prevents data from passing in either direction across it under user defined rules. You SHOULD have one on your connection to the Internet if nowhere else.

Anti virus

Every Computer should have an anti virus program running on it unless you can absolutely guarantee there is no chance of a file or program being put on it via disk or network connection and that includes memory sticks CDs etc.
Use a proprietary Antirust program which has regular updates.

Passwords

Big dilemma here. If you have a different password for each system you login or connect to then it will be very difficult for someone to get into the system using your access. On the other hand once you get more than a couple of passwords to use then you may need to write them down in order to remember them which has just defeated the point of having a password.
If you have the option to change your password then try the following:- Break your passwords up into different categories, like work, home, Banking, other. Now do not use one password in more than one group, This still requires you to have multiple passwords but they can be made up in different ways like. Home passwords can be simple like your name or your date of birth. Work can be something like yourname and the month you started or your company ID number. Banks have their own system but again make it memorable and only use it for banking.
To make passwords much more secure click the Passwords link.

Simple firewall