PC Security

Email, Spam & Instant Messaging

  • You can avoid almost every virus and spam email by simply reading the subject line and deleting irrelevant junk. Most spam emails are from people you do not know, for products you did not request or contain obvious spelling mistakes to bypass spam filters. You can recognise these easily; just delete them! Resist the curiosity to read them.
  • Opening spam or infected emails often alerts the sender that they reached you (by perhaps reading a picture file from a remote server). It can also trigger some viruses automatically. Try to read the subject line first and avoid opening emails that are junk. Please note that the so called 'Preview Pane' has to open emails to display the contents so its best NOT to use this feature.
  • You should be VERY suspicious of emails asking you to 'confirm' your details by following a link. Although these emails and web sites may, for example, display your bank's branding they are very easy to fake. This practice is known as 'phishing'. You should only enter private information (such as passwords, pins, secret words) on sites that you know (e.g.: from previous use) or find on search engines. Actual examples can be found on the Anti-Phishing web site.
  • If you receive an email with an attachment, please 'Think before you click' on any attachments. Attachments are often viruses so never open them unless the sender is known to you AND the file name matches the context. But even then......
  • Be warned that if one of your friends has a computer that has been infected with a virus that the virus may send you an e:mail that appears to come from your friend...or indeed anyone else in their address book...so be suspicious of strange wording or requests to open/run files.
  • Delete 'chain letters' and unsolicited warnings about viruses and other threats. These are often easy to identify because they ask you to send them to others. Don't! They are usually hoaxes.
  • Avoid submitting queries or joining discussions on web sites which cannot hide your email address. These are harvested for spam and you open the door to more and more junk mail.
  • Spammers often make up names which sound believable or interesting to entice you to open the email (eg: support@microsoft.com). You should be suspicious of emails from people that you do not know. Never reply to them (or 'unsubscribe') as this will simply confirm that they got through to you.
  • Instant Messaging risks are similar to email. Avoid unsolicited messages and attachments. Never 'share' files or folders. Remember that all messages travel over the Internet so never use Instant Messaging for sensitive discussions.

Internet Usage

  • If possible try to only visit web sites that you know and trust, or perhaps have been recommend to you or those that have been found with sensible queries on a search engine.
  • Note that links in emails and on web sites can be misleading. They can take you to sites that you were not expecting so be wary when you follow 'interesting' links.
  • You would normally be cautious dealing with a 'street vendor' so take similar precautions on the Internet. Only buy from or submit sensitive information to sites that you trust.
  • When you do decide to use your credit card or submit sensitive information (eg: to your bank), expect to see the URL starting with 'https' and the SSL padlock closed (locked). SSL makes sure nobody can intercept the data as it travels over the Internet and is trusted by banks.
  • In general ignore popups because they usually have nothing to do with what you were looking for. Close them with the standard 'X' in the top right-hand corner rather than any 'close' button on the screen to avoid any other trickery they may have built into the popup.

Viruses & Spyware

VIRUSES CAUSE THE MOST DISRUPTION TO PC's and spyware can be extremely annoying. Please follow the following precautions:

  • As described above, delete junk emails unread and 'Think before you click' on any attachments. This will avoid most virus problems.
  • Never follow the instructions of someone you do not trust to download or open a file.
  • Keep your virus guard up-to-date...new viruses appear all the time and an old version may give you a false sense of security.......
  • Computer files should always have a file name followed by an extension (eg: readme.txt). Files with extensions such as .doc, xls, ppt, txt, jpg, bmp are usually safe but you should still think about where they came from as malicious code can be embedded into them.
  • You need to be very VERY cautious with 'executable' files or ones with extensions you do not recognise (eg: .exe, com, bat, pif).
  • Always avoid files which have double extensions (eg: readme.txt.exe).
  • 'Spyware' makes your browser display sites you do not want, and 'key stroke logger' software can capture your passwords and other sensitive information. You should generally just ignore and close unsolicited pop-up windows.
More on Spyware.....


Should you click on messages like this?


Search (e.g.) Google for 'free clipart' or 'free software' and you will find loads of sites which generate popups like these.

What can happen? It is common for your browser's home page to be changed to take you somewhere different. Clicking a link to 'check your PC' can mean 'load tracking software' or 'enable remote access'. They can make windows pop up randomly and be very annoying! These and many other exploits usually go by the name 'spyware'.

A 'key-stroke logger' is another variant which can capture your passwords. Even well-meaning tools like the Google Desktop can take copies of sensitive documents including emails, presentations and web sites you visit. So what can you do...?

  • Be cautious when you reach a site with popups.
  • Close unwanted popups with either the 'X' in the top right-hand corner or by selecting 'Close' from the popup menu when you right-click over the window's icon on the task bar (see example above).
  • Be verycautious about what you install on your PC.
  • Check your browser's cookie settings and accept 'First Party Cookies' and block 'Third Party Cookies'. These options differ across versions and may be found on the Tools menu (eg: Internet Options, Privacy tab, Advanced button)
  • Don't visit dodgy web sites!

Anti-virus products are starting to search for spyware. However, you often need specialised 'anti-spyware' software (e.g. Spybot) to sort out infected PC's.


Passwords are 'keys' to information so they need to be protected:

  • As a general rule, never divulge your passwords to anyone.
  • If you have to write your passwords down, keep them where others cannot find them (ie: not in your desk drawer, under your keypad, etc.). If you keep them in an electronic file, make sure the name is not obvious (eg: not 'Passwords'!) and password-protect or encrypt the file itself. You can get a free encrypted folder system called Cryptainer.
  • If you think someone may have discovered an important password, change it immediately (and if appropriate notify anyone relevant...eg. your bank).
  • It is OK to use the same password for unimportant things (eg: many web sites require a password).
  • Always use a different password/pin for your personal bank accounts. If you use the same one for multiple bank accounts you are likely to be in breach of their conditions and they may not pay out in the event of a claim.
  • Try to create passwords which are hard to guess but easy to remember.
  • A password which only uses 'alpha' characters is weak (azyoqvih). If you use words which can be found in a dictionary they are even weaker (george).
  • 'Alpha/numeric' passwords are much stronger and are easier to remember when you use mnemonics. You should use alpha/numeric passwords even when systems do not enforce them.
  • Passwords which also have 'upper/lower' case and 'special' characters (eg: #~@') add enormous strength. These are required for system administrators.

Protecting Your Home Computer

Do you store digital photos, emails and other useful/important documents on your PC? Worried about buying online or your kids using the net? You can take some simple precautions with very little effort or cost:

  • With viruses being as common as they are, make sure you have anti-virus software. ideally set it to update automatically and let it do its job. Symantec and McAfee are popular commercial products and AVG and AVAST are (at the time of writing) free for most homes.
  • You also need a 'personal firewall' whichis a software barrier which filters out most of the other ways of attacking your PC. If you have Windows XP at home, switch on the Windows firewall or install the free ZoneLabs product. Many commercial anti-virus products have firewall options as well.
  • All software has programming errors or bugs and these are often exploted by viruses. Suppliers fix these with update programs referred to as 'patches'. Enable automatic updates on Microsoft systems or update at least monthly if done manually.
  • 'Wireless' is the easiest and most convenient way to make a home network. However, the radio waves travel through walls and do not stop obediently at the edge of your property. You should enable 'WEP' to prevent your neighbours from eavesdropping your activities, connecting to your PC and indeed using your broadband for free!
  • Be cautious about installing free software from the net. This may install spyware. Only download programs from sites you trust (eg: Tucows). If you use Windows XP, always create a 'restore point' before installing new software as this often allows you to back out the installation if it goes wrong.
  • Hard drives do fail sometimes so backup everything you cannot afford to lose at least monthly. This should include emails/addresses, digital photos, documents you have created, favourites, etc. A CD or DVD - writer is a useful medium for this as is, perhaps, a second hard drive.
  • If you have children who want to access the net, visit Childnet for advice. Young ones may enjoy the Hector Protector.
  • Want some advice about online buying, Consumer Direct have loads of tips.
  • Looking for other solutions? PrevX offers free 'behaviour blocking' software for home to supplement anti-virus.


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