Q. I still use Windows XP, but I've heard that Microsoft will not be supporting it from 2014. Is it safe to keep using it, or do I have to upgrade both the operating system, and quite a number of applications that will not run on later versions?

A. Microsoft will stop releasing patches and drivers for XP after April, 2014, but XP will carry on functioning perfectly well. There are something like 500m people and business still running XP, so there will be plenty who will keep on using it for sometime yet. In theory, over time, your PC could become more vulnerable to attacks by malware but, if you keep your third-party antivirus up to date, I don't think that there is a big risk at all. You will still be able to activate XP if you need to re-install it, but you will find that the latest peripherals - such as scanners and printers - may not work properly with XP because of the lack of suitable drivers. Providing updates to your third-party antivirus software continue to be available, XP should be good for a few more years yet!

Q. When I upgraded to Windows 7 from Windows XP, I asked a local PC business to do it for me. When the PC was returned, I was horrified to discover that all of my family photographs had been deleted from the hard drive. Are they still there somewhere, and could they be retrieved?

A. I fear that they are completely lost if the business did the conventional installation of the replacement operating system over the top of the old one. It is possible to install a new operating system alongside an old one, in which case they will still be there, but that would be most unusual unless they were specifically asked to do this, and if they had then you should see an operating system choice when you start the PC. It would be usual for a shop to ask specifically whether you had backed-up, or otherwise saved your data, before starting this sort of job. Even if you don't remember them doing this, it is worthwhile asking them if they made a back-up copy of the hard disk before doing the work, but do it soon because they wouldn't keep such copies for long after a job appeared to have been satisfactory. There is an adage in the computer world to the effect that data doesn't exist until there are two copies of it. There are a number of ways of taking this second copy, which don't have to be expensive. One can use a USB stick, an external hard drive, or free cloud (i.e. online) storage capacity such as Dropbox.

Q. I recently upgraded to the latest version of iTunes, since when my computer can't recognise my iPod. What might the problem be?

A. Whilst it is possible that the iTunes upgrade is the culprit, the most likely causes are simple physical ones. Check for damage or dirt in the iPod's socket. Fluff can easily cause a problem. Blow hard into the socket to dislodge any dust or dirt. If that doesn't work, try plugging the USB cable into a different port on your computer. If that doesn't work, try using a different USB cable. If that doesn't work, uninstall iTunes, download it again and then reinstall it. (Your music won't disappear!) If none of this works, then go to http://support.apple.com/kb/TS1363, where Apple suggests some procedures that you might try.