Q Ten days ago, I bought a new notebook running Vista Home Premium, but the hard disk is already showing 47GB of space used.

Around 22GB can be accounted for by the Program Files, Users and Windows folders but there is no clue as to where the remaining 25GB has gone.

Strangely, my old computer with Windows XP Home is in a similar position, showing 87GB of content of which I can only account for 44GB.
Alan Dick

A The most likely culprit for this missing space is System Restore. System Restore is a form of backup for Windows, but rather than keeping your files safe, it protects drivers, settings and other essential parts of the Windows operating system. A backup made by System Restore is called a Restore Point. It is particularly useful if a driver upgrade goes wrong or for reversing a problematical software installation.

To change the System Restore settings in Windows XP, left-click on the Start Button and then right-click on the My Computer icon. Select Properties from the menu that appears to see the status of System Restore on the computer. Left-click on the (C:) icon and then on the Setting button for more information. The slider can be used to adjust the amount of hard disk space used for the System Restore files.

No more than 12 per cent will ever be used. Left-click and drag the slider to the left to reduce the amount of space used by System Restore and free it up for other uses. Bear in mind that reducing the System Restore space will reduce the number of restore points that can be made.

It is not possible to adjust the amount of space used by System Restore in Windows Vista. System Restore needs a minimum of 300MB and will use up to 15 per cent of the hard disk. As this limit is reached, old restore points are deleted automatically.

The only alternative is to turn System Restore off altogether.To do this, left-click on the Start Button and then
right-click on Computer. Select Properties. Left-click on Advanced System Settings and then on Allow if the User Account Control window appears. Click on the System Protection tab and then in the small box with a tick next to the hard disk.

A message will appear to confirm the change, click on the Turn System Protection Off button. The tick will then disappear. Click on OK to close the window.