Q Can I keep my current phone number when I transfer mobile networks?

AM, London

A Yes, you can — and usually without charge. Ask your current service provider for a PAC (port authorisation code), which you will need to migrate your phone number to another network. You then pass this code to your new mobile network when you apply for its services. Your old network must give you a PAC (or a valid reason for not issuing one) within two working days, although the whole process can take up to a month.

If you ask for a PAC before your minimum contract period is completed, there is likely to be an early termination charge.

Q My five-year-old PC has slowed down. Would cleaning the registry help?

DB, Berkshire

A The registry is a part of Windows that stores settings that other software programs need to run properly. After a while, it can become cluttered with the remnants of old deleted programs and this can make a computer grow sluggish.

You can optimise an ageing PC by giving its registry a spring clean, using either the basic tools built into Windows or a dedicated piece of software such as CCleaner (free from www.ccleaner.com). Proceed with caution as mistakes could mean you had to reinstall Windows.

Q When I create electronic versions of paper documents as PDFs using my home scanner the files are enormous compared with when I scan them on my office machine. Is there a way round this?

CS, Cheshire

A The size of these scanned files is often dependent on the scanner hardware that you are using and, if so, there’s little you can do. Check your user manual to see if your scanner gives you the option to lower the quality settings, either on the device itself or on the supplied computer software.

Another option is to adopt a two-stage approach whereby you convert each file into a PDF after it has first been scanned. This should give you more control over the level of compression and resultant file sizes, especially if you use good software such as PDF Compress (free at tinyurl.com/2mmury).

Q Can you recommend a simple replacement TV remote control suitable for a 90-year-old with slightly clumsy fingers?

PF, Bromsgrove

A The One for All Zapper TV remote control (£7.99 from tinyurl.com/kkc5qv) is what you need. This basic TV remote has just seven buttons and its simple design won’t intimidate anybody. It does need to be carefully set up before it can be used for the first time. Check the Zapper will work with your TV (see www.oneforall.de ) before you buy one.

Q What can I do to improve the consistency of my Freeview digital TV reception? The stations all seem to flutter much of the time and are worse in the summer. This never happened with analogue TV.

PW, East Yorkshire

A Given that your problem varies in severity, the culprit is far more likely to be the aerial than the TV or set-top box. That said, there’s nothing to be lost by getting your TV tuner to rescan the Freeview stations automatically. While you’re at it, check that all the cables are undamaged and in situ.

With Freeview, it’s important to use a decent external TV aerial that is well positioned. You may suffer from reception woes if there are, say, tall buildings or trees that obstruct the aerial’s line of sight to the local transmission antenna. Heavy snow or rain might hamper picture quality but the reception can also sometimes worsen in the summer, as nearby trees have more foliage then.

There is detailed advice on aerial-related ills at www.digitaluk.co.uk

dontpanic@sunday-times.co.uk

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