Q. Following a young family member's advice on defragmenting my hard disk, I tried to do this. However, I was thwarted by a lack of space. The hard disk capacity is reported as 28.63GB with 3.76GB storage space left. According to Windows Disk Defragmenter, 15 per cent of my hard disk must be available for the defragmentation to proceed. However, my disk has just 13 per cent of its space free. I have a fear of deleting applications and files, not least because everything looks like it is required. What can I do?

A. I don’t have a lot to go on, because you didn’t tell me what programs you have installed or even which version of Windows you’re running. However, the size of your hard disk suggests an older PC, so I think it’s a fair guess that you’re using Windows XP. If so, I think your best bet is to use the supplied Windows Disk Cleanup utility to free up some space. Typically, this won’t free up huge amounts, but as you only need to reclaim a little to get above the 15 per cent threshold Disk Defragmenter demands, I think it will help. To launch it, click Start then point to All Programs, followed by Accessories, then System Tools. Click on Disk Cleanup. The utility will spend a few minutes analysing your PC’s hard disk, looking for files that can be safely removed. This will include temporary internet files and the contents of the Windows Recycle Bin. Where possible, it will also offer to compress old files, but I don’t recommend this. Use the tick boxes to make your selections, click OK and then click Yes to confirm that you’re happy for Disk Cleanup to make the changes. When it’s done, try Disk Defragmenter again. If there’s still not enough free space to proceed, launch Disk Cleanup again and click the More Options tab. Use the three options there to safely remove more stuff from your PC. Click the Clean up button in the Windows components section, for instance, to select and safely remove aspects of Windows that you don’t use or otherwise don’t want – such as Windows games, say. Click the Details button to find out what will be removed. If there’s still not sufficient spare hard disk space for Disk Defragmenter to go about its business, then consider temporarily moving some or all of your personal files (those in My Documents, My Pictures, My Music, etc) to an external storage device, such as a USB memory key. When Disk Defragmenter has tidied up the hard disk, they can be copied back.

Q. My Mac has a disc stuck in its drive. Although the drive makes a whirring noise as if it is trying to read the disc, there is no icon on the desktop so I can't click on it to eject the disc, and I can't find an eject button. What can I do?

A. Look in the Utilities folder in Applications. This will list your Mac's optical drive(s), and the disc that it contains. Select the disc, and then click on the Eject button at the top of the window. If that doesn't work, restart the Mac. After the start up sound, press and hold the mouse button (or trackpad on a laptop), which should force the disc to be ejected.