Q. I print from my iPad to an HP wi-fi printer, which has its own open hotspot. (My home network is secured.) How may I add a password to the printer's hotspot?

A. This situation applies to many wi-fi printers. Not only could someone use your printer for their own printing jobs - not really useful since they'd have to collect them from the printer unless they want just to annoy you! - with even limited technical knowledge they could intercept documents sent for printing, and access those stored in the printer's memory, though HP have closed this latter loophole in the latest versions of the printer's firmware. So, the first thing to do is download the most recent version of the firmware from the manufacturer's website and install it, and to check regularly for updates. It is not possible to add a password to HP's printer wi-fi hotspots so turn the hotspot off when not using it. For really sensitive documents, transfer them to a USB stick and print directly from that assuming that the printer accepts USB sticks.

Q. The paid-for security packages are quite expensive, and there are a number of free ones - such as AVG - available, but do the free ones provide sufficient security for online banking and shopping?

A. No security package provides 100% protection. I can't speak for all of the free packages, but Avast! and AVG seem as good as the paid-for ones at detecting attacks on PCs. If you are using a free package, I would recommend also using an anti-malware program too. A good free one is Anti-Malware, and keep it up to date. Other simple guidelines that should keep you safe are: never download software unless you are absolutely certain of its provenance, never believe too-good-to-be-true e-mails, don't ignore warnings about websites from your browser, and use strong passwords that should include as a minimum numbers and both upper and lower case letters.

Q. When I launch my web browser and connect to GMail it automatically logs into my account. While I can see how this might be useful, I would rather it did not do this, as this computer is used by occasional visitors, including our teenage grandchildren. I sure it did not used to do this because I always had to type in my password, so what has changed? And how can I stop it?

A. The most likely cause is that you have inadvertently clicked the ‘Stay signed in’ tickbox that appears just below GMail’s username and password boxes when logging in. It is right next to the Sign in button, making it very easy to click accidentally. When you do this, GMail places a cookie on your hard disk that is used to sign you in automatically the next time you visit the service using the same computer. This cookie has an expiry of two weeks and is renewed every time you visit www.gmail.com (in other words, unless you happen to leave more than two weeks between visits, you will continue to be signed in automatically). The solution is very simple. Once logged in, click your username at the top right of the GMail window and then click the Sign out button. Next time you log in, check that the ‘Stay signed in’ tickbox is left unticked.

Q. How may I protect my e-mail address from spam?

A. Well, the short answer is that you cannot, unfortunately! However, there are a few steps that can be taken to reduce your exposure to it. You may want to consider having more than one e-mail address: use one address whenever you sign up for anything on the Web, and give your other address only to people you know. When you do get spam mail, never reply or click on a link offering to remove you from their mailing list. This will only confirm your address is real and you will then get even more spam. Never sign up for any spam e-mail opt-out lists, these are just another attempt to get your email address, or worse, money. It is important that you have up-to-date anti-virus software. If a virus infects your PC it may try to use your address book to spread itself through e-mail spam to all your contacts. Visit www.getsafeonline.org for more advice about spam prevention and security online.

Q. This is a safety hint, rather than a response to a question.

A. Even if you work really hard at avoiding viruses and other malware, you should prepare yourself for the chance that one will make it onto your computer anyway. Backups protect your files from being deleted, but what protects your sensitive files from hackers? The only thing that can protect your sensitive files is encryption. Higher-end versions of Windows include encryption, but you can also download a free encryption utility that provides just as much security (if not more: Microsoft is under pressure from some governments to put a "back door" into their encryption). To secure your files against hackers and other prying eyes, I suggest the free TrueCrypt encryption software.

Q. Some time ago I mentioned a product called Trusteer Rapport in the context of banking security. (Click here to see the article.) I have now been asked by someone whose bank recommended the product, how safe the product is to use since it produces long, alarming sounding, error reports. Might it be stopping valid processes/actions from being performed?

A. Yes, it is a safe product to use. The rather alarming looking error reports are the result of both malicious activity directed at your PC across the Internet, and also coding errors by the people who created the websites. There is a downside to it however: it is quite a resource hog. If you have an older computer, you are likely to notice a significant slowing down of many processes. If it is really annoying, then uninstall Trusteer Rapport and rely on whichever Internet security package you are using.

Q. I want to be able to store all of my passwords, and personal data, securely on my Windows computer. Do you have any suggestions?

A. There are a number of options for storing passwords and personal data on a computer. The one that I recommend is the free KeyWallet, which uses good quality encryption, and for which you create a master password. Make sure that the master password is at least eight characters and includes numbers and both upper and lower case letters.

Q. I bought a second-hand iPhone, and put my personal data into it. However, when it lost charge, it would not restart, so I have arranged to return it for a refund. I'm worried though that my personal data - such as Facebook login and e-mail details - could be read by another purchaser once the problem is resolved.

A. Once a new battery has been fitted to the iPhone, which is the probable problem, you are right that your data will be accessible. You would be better advised not to return it but to pay Apple to replace the battery. (Apple don't like you to do it yourself.) This will cost about £50, plus P&P if you can't get into an Apple store yourself. If you decide to stay with returning the iPhone, at least change your passwords for services like Facebook and your e-mail using your computer. Other data should have been wiped when the battery failed. For the future, I recommend too using a passcode, which you'll find under Settings/General/Passcode Lock on the iPhone. Then, if the handset is lost or stolen, any new user would be forced to restore to factory settings, erasing all personal data in the process.

Q. Is a camera memory card a possible source of infection? I sent one from my digital camera to a supermarket photographic service to have some pictures printed. After its return I found a Trojan on my computer.

A. Congratulations on spotting the Trojan! It is certainly possible for a memory card, or any other storage device, to be infected. Proving that your card was infected by the supermarket would be very difficult because there are so many possible avenues - e-mails, websites, downloads, swapped memory sticks - through which malware might infect a computer. The lesson, of course, is to always use anti-virus software and to scan anything that you connect to your computer, or download onto it.

Q. When making online purchases, I always enter credit card details using my mouse and a virtual keyboard, rather than the actual keyboard, to protect myself from keyloggers. A friend says that I'm wasting my time. Is he right?

A. He is, I fear. Keylogging software sits on an infected computer and records all key depressions, which can include passwords and credit card numbers, but this type of malware can also record the location of your mouse pointer every time a mouse button is pressed. Some websites circumvent this by giving you a virtual keyboard to click on where the numbers and letters are in random positions so that the logged mouse clicks will be incorrect. Common sense and correctly maintained anti-virus software should be all you need to avoid trouble making online purchases. Make sure that your computer's security features are turned on, never open an e-mail from someone you don't know, believe your browser if it warns you that a website is suspicious, and install good anti-virus software such as Norton or McAfee, or the free AVG.

Q. Want to be able to track your laptop, smartphone or tablet computer if it is stolen or missing?

A. If you do, there are several software products to help you do so. One of the best is Prey, which is available in both a free version adequate for most people's needs, or a paid for version with some extra features. The program works in the background unknown to the thief, sending information on the device's whereabouts, and what it is being used for, to either a control panel accessible via the Internet, or a pre-defined e-mail address. It is even capable of sending images from a laptop's webcam of the person using it!

Q. Am I still covered for loss if I use a computer for banking online, but without having security software installed?

A. This is more of a legal/insurance question than a technical one. Liability for breaches of security differs between banks, but the usual position is that providing you have not been careless with your details such as PIN, password or other logon security information, you are covered. Having said that, you shouldn't ever connect to the Internet without security software installed! Click here to see what I have said previously about security. Another product I would recommend, that your bank may already offer for free, is Trusteer Rapport, which works through your browser to make sure that it is indeed your bank's website that you are logging on to.

Q. Should I use any special software to stay secure when using a public Wi-Fi hotspot?

A. The short answer is no, but as with any surfing it is a matter of good security and prudent safe behaviour. Ensure that you have up-to-date anti-virus software installed and running (discussed in a previous tip). Make sure too that a software firewall is active on your laptop. If your anti-virus software doesn't provide a firewall - the free ones don't - then use Microsoft's, which is provided from XP onwards. To check if it is turned on, go to the Security control panel. Try to visit only the secure versions of websites. They start with https, where the s stands for secure. Secure sites display a small padlock next to the address in the browser. Finally, watch out for anyone standing behind you, or displaying a particular interest in what you are typing: they may be trying to pick up your usernames and passwords!