Rob Freeman, Click's very own Mr Fixit, troubleshoots your PC problems and helps you get the most out of your computer.
If you use a computer at your workplace - or even at home - you will probably be very familiar with the concept of logging on using your own username and password.
But the chances are that if you are at home, all the members of your family use the same account to log into the internet.
If you do not do this hang on for some special tips for you in a moment; but if I just described your home computer, particularly if you are running Windows, I'm going to explain why using a single user for everyone is a very bad thing.
The first thing to do is set up a different username for each person, and this is almost like creating a different computer for each person.
Go to your Control Panel, and choose User Accounts. You have to be an Administrator to do this (more about that in a minute). Press Create a New Account and enter the name of your new user.
On the next page, you have an important choice. There are two main types of users within Windows: administrators, who can control everything, and limited users, who have less control.
It is a bit like a plane - like the pilot, an administrator gets all the controls, and a nice seat at the front, while a limited user still gets to be in the plane, but their controls are a little bit smaller.
Limited users can surf the web, they can send and receive email, they can run most software which has been installed on a computer. But they cannot change important system settings or install most software programs.
This is the important bit: if a limited user cannot do those things then a virus, or Trojan, or any other nasty bit of software that gets onto your computer, cannot do them either.
You can see now why that admin account is very powerful, and should not be used for day-to-day work.
It is much safer to run your computer in limited user mode for the vast majority of the time.
This is much more about protecting the computer from outside attack than it is about restricting what the users can or cannot do.
There is also the safety net that if you are a limited user, you cannot accidentally delete critical files which might stop your system working.
If you are already using a number of different users - well done! However, you might like to check how many of those users are administrators, as Windows will make all new users admins by default.
How to change accounts
You can check and change account types in the Control Panel. Select Change an Account, pick the Username and then press Change the Account Type.
Top Tip: Have one administrator account on your system, and make everyone else a limited user. Even if you are the only person who uses your computer, create a second limited account.
Windows makes it easy to switch between users if you need to make a quick changes or install software.
This is a feature called fast user switching, and it is something you will see on Mac OS too.
Normally when you log off, all the programs you have been using are closed. Fast user switching means that when you go to the log off screen and choose Switch User, everything you have been working on gets frozen, while you log into the second account.
When you are finished, you can switch back and pick up exactly where you left off. It is a great time saver.
Sometimes as a limited user, Windows just will not allow you to run certain software and that is where the very handy Run As command comes in.
This lets you run a program as if you were an administrator.
How to use it
Bring up the icon of the software which will not work. Hold down shift, and press the right mouse button. Choose Run As. Now enter your Admin login and password and that software should work normally.
There are lots of extra benefits to having separate user accounts. It means each person has their own private area to store their files in, they can keep their email accounts separate from other users, have their own internet bookmarks and customise their own desktop.
My favourite aspect is actually one of the simplest, which is being able to customise the pictures in the login screen.
The setting for it is back in the Control Panel, under User Accounts, and you click on Change My Picture. There are a small number of images to choose from, but easily missed at the bottom is a link to browse for more pictures.
This means if you have got some of your own images, from a digital camera perhaps, you can use them instead. It makes the whole thing much more personal.
We get frequent criticism for not saying enough about Macs.
This is going to be one of those times where I do not say a lot, mostly because if you are on OSX then you are not nearly as at risk from these issues as Windows users, but just so you do not feel left out, here are some web addresses (www.informit.com and http://en.wikibooks.org) where you can find out how to set up and customise additional users in OSX.