Q. I use a MacBook Air, which works well at home using wi-fi. However, I can't get online when I try to use it in places like pubs, hotels and coffee shops. Why?

A. Many public wi-fi spaces have their router hardware tucked away, and so may not be providing a strong enough signal. Plus, the more people who use such a service, the the worse the service will be. However, I suspect that the problem might lie elsewhere and be simple to deal with. If you are seeing a signal strength of at least two to three bars/lines, then it is probably just that you need to sign in to the service: a lot of public wi-fi services require you to sign in before you can use their service. To sign in, when you can see the network signal strength bars, just open your browser (presumably Safari). After a few seconds, you should see a registration screen. Complete that, and you should be "good to go". Next time that you're in the same place, Safari should remember your registration details for you, but you will still need to open Safari to get connected.

Q. Is it possible to use Bluetooth to connect my hi-fi to my Sony soundbar to play music?

A. Probably! Most recent soundbars/sound plinths come with Bluetooth receivers, and are rather good music speakers. You will need to buy a Bluetooth transmitter and plug it into the hi-fi headphone socket. Bluetooth transmitters start at around £40; the Aventree Saturn is a good one.

Q. My iPad's 3G SIM card works in the UK, where it was issued, but not when I'm in France. How can I connect in France?

A. The first thing is to check with the SIM card's supplier - O2, Vodafone, etc. - that it has been set to allow "roaming". It may be restricted because roaming charges can be very high. Check out the data roaming costs with your operator before having roaming enabled! If you visit France regularly, and your iPad is not locked to your UK network, it would probably be more economical to buy a SIM card from a French mobile supplier for use in France. For example, Orange France charge around €150 annually for a 1GB package. Or find somewhere local with free WiFi!

Q. Why do online music tracks, and videos keep cutting out whilst I'm listening to or watching them?

A. Browsers generally load only part of these files before they start playing, while the rest of the file is still being downloaded. This means you don't have to wait too long to hear/see anything, but sometimes you may catch up with it and it has to stop until it has downloaded the rest of the data. If you find this annoying, you could press pause and then wait for the loading bar to reach full before playing the file.

Q. I read somewhere that I should be able to connect my Kindle to my computer using a USB cable, and transfer e-books to my Kindle. However, when I connect the two, the Kindle goes into an unresponsive battery charge mode. What can I do to connect them properly?

A. A USB socket carries electrical power and, providing that the device being attached doesn't demand too much power, it will be recharged whilst data is being transferred. When connected to a PC, or Mac, the Kindle should display USB Drive Mode after a second or two, and should also appear in My Computer on a PC, or as mounted on a Mac. When that doesn't happen, disconnect and restart the Kindle, then go to its Home screen, bring up the menu, select Settings, then select Restart. If that doesn't work, then try connecting the Kindle to another USB port/socket and, if possible, try a different USB cable. Some Kindles are reported to have excess plastic around their USB ports, so check and make sure that the cable is fully engaged. If none of this works, then you may have a problem Kindle, and you should contact Amazon Customer Support via the Contact Us button at http://www.tinyurl.com/ye7fvr3

Q. I have a surround-sound system connected to my television, and the system has a USB socket. I'd like to show some photographs from my Canon camera on the TV, but when I plug the camera into the USB socket I see a message saying "USB failed". What is the problem?

A. The surround-sound system is an audio device, not a picture viewer, so the most likely cause is that it doesn't support USB-connected cameras! However, if you are certain that the system can handle images, then check that the ones stored on your camera are in a format that it can read. JPEG/JPG is the closest format to a universal one, and most cameras use this format by default. High-end cameras, such as those favoured by professional photographers, tend to store RAW images - a high quality uncompressed format - most unlikely to be recognised by a sound system. Look in the back of the sound system's manual, or the maker's website, to see what formats it can work with, and then adjust your camera's settings to save in one of them.