With Vista looming, many of us will use the launch of a new and radically different operating system to make the move to a new computer. You may be planning to ease the financial pain by selling off the older system, or intending to gift the cast off to a recycling scheme. But, as regular visitors to these pages will know, passing on a PC to a new owner has serious security implications

This article appears in the March 07 issue of PC Advisor, onsale now in all good newsagents.
Before a PC can be safely rehomed, it's vital that all data is thoroughly cleared to prevent it turning telltale and spilling sensitive information. Believe us, it does happen.

Contrary to popular belief, when a file is deleted the data isn't removed – the reference to the file in the file system table is all that's removed. And so the original data remains, until another file is written over it.

Formatting a hard drive scrambles the data and provides a clean slate, but even this isn't enough. A growing number of data-recovery tools enable people to piece together traces of deleted data, even after a low-level reformat.

Whether or not you're migrating to a new PC, it's a good idea to get into the habit of periodically deleting files. A thief could get hold of your important data months or even years down the line. This may sound like doom-mongering, but it's far from an impossible scenario.

Thankfully, there's no shortage of data-shredding programs that make it extremely difficult – if not virtually impossible – to recover deleted files. In the March 07 issue of PC Advisor we've used the free Eraser 5.8 (it's on the March 07 cover DVD), which overwrites previous data.