Skip to content The Open University

Skills Check 0

The Skills Check is a short survey which should take you no more than 3 minutes to complete. Once you have completed the Skills Check we provide you with a personal learning plan targeted to your personal study needs and goals.

Sign in to work on the Skills Check.
  1. Home
  2. Computing skills
  3. Computer security
  4. Protecting your PC

Protecting your PC

The internet can be a fun place to explore, but it is important to protect your PC from the threat of viruses and other attacks.

What is a computer virus?

Computer viruses are hidden or secretive programs that you can acquire while online. They may have been programmed to copy information from your machine, damage its contents or, increasingly, to turn your computer into a 'bot', which allows hackers to use your computer to send unwanted ('spam') email to other people. Your computer can acquire a virus if you click on an attachment in a malicious email or if you click on a link to a suspect website.

When infecting a computer a virus can delete and destroy your files and it can also use your email and its address book to deliver itself to your friends and colleagues. Use the following rules to keep your computer virus free. For further information on specific viruses and threats visit the Open University - Antivirus website

The dos and don'ts of computer security
Do Don't
Install and regularly update some anti-virus software and a personal firewall Download software unless it is from a reputable source
Get the latest patches and updates for your operating system Send private information in emails, especially banking details
Regularly back up your files Buy pirate copies of software
Ensure you have the latest updates for your operating system installed Open email attachments, unless you are sure they are safe

Anti-virus software

The best way to avoid getting a virus is to install some anti-virus software. This automatically checks what you do on the internet and scans for viruses. If it spots a virus hidden in an email message or web page it disables the virus and prevents it from damaging your computer.

New computers are frequently supplied with a free three-month trial of anti-virus software for which you can pay to continue using after this period. There are also a number of free anti-virus packages.

It is also important to keep the software up to date so new threats are detected. Anti-virus software will often automatically prompt you to update it, which involves connecting to the internet and downloading specific files.


A firewall is a barrier between your computer and the rest of the internet. It monitors data passing between your computer and the internet and checks it against a set of 'rules'. The rules you set up will protect you from hackers (people who try to access other computers illegally) and the programs they write, such as worms and viruses.

Both Windows XP and Vista have a firewall but it's important to check that it is turned on.

A firewall can occasionally prevent some essential activity, such as downloading a legitimate file. However, you can turn it off temporarily or adjust the level of security to a lower setting for a while.

Firewalls and other types of security features are usually integrated into modern security software suites.

Some Internet Service Providers (ISPs), like BT and AOL, provide a free copy of a firewall program to their customers.

Keeping Microsoft up to date

You can find security updates for Microsoft at their Download Center. The updates are usually big files but you can also find smaller 'patches' to fix known problems. Other operating systems have similar sites.

A virus in your email

Viruses travel using email but they cannot be transported through a text-only message.

The only way a virus can be carried in an email is through an attachment. You can tell if your email has an attachment, as it will show up in emails as a paper clip (pictured right), or a small picture (icon) of a piece of paper.


If you do not recognise the email address of the person sending you the attachment, be very wary of what the attachment contains. Even if the attachment comes from someone you know, unless you were expecting it, check with them before you open it.

People who make viruses often use tricks to encourage you to open the attachment, such as pretending it is a joke or a picture of something funny. They may also try to trick you by using wording such as 'Urgent' or 'Read now' to make you open the attachment.

The golden rule is do not open any attachment unless you are confident you know what it is, or trust who has sent it to you. Delete any messages you do not trust and you will be saving yourself a lot of trouble.


Phishing is malicious activity designed either to damage your computer or copy information from it. Phishing emails work by posing as legitimate emails that either ask you to click on a link, or reply sending private information, usually regarding your bank account. An email received from someone you do not recognise or that asks for private information should always be treated with caution and the safest option is not to answer it and to delete it.

Only use reputable software and programs

One other way to ensure that you will not get a virus is to make sure you only use official copies of software on your computer. Do not download any software unless it is from a reputable source, and do not buy pirated copies to install on your PC. If you do not know where the software has come from it may be infected with a virus which will then infect the rest of your computer and possibly destroy other programs.

Backing up

It is a good idea to get into the habit of regularly backing up your work files - things like your notes and assignments. This involves making a copy onto another storage device such as a hard drive, CD-ROM or memory stick. If anything goes wrong with the hard disk on your computer and you lose all your data, it is some compensation to find that you have a recent copy of your files.

To avoid losing important system files that run your computer, back them up using a data storage system such as a CD-ROM or portable hard drive. Alternatively, upload your files to one of the dedicated websites that provides web storage space, possibly for a small fee.

Other information