How much are you willing to pay for peace of mind? Take your PC, for instance. When it comes to its useful/valuable/irreplaceable collection of data (delete as applicable), we reckon that the cost of a decent meal out for two is a fair price to pay for back-up software.

However, the software's called O&O DiskImage, and so perhaps "back-up" is a misleading term. It won't enable you to schedule regular backups unlike, say, Norton Save and Restore 2006, which might take into account changes to the My Documents folder.

Instead, O&O DiskImage will take a snapshot of your hard drive that'll encompass every piece of data, including Windows files. Once the image has been created it's held on a new partition on your hard disk. It's also possible to save the compressed file to an external drive or burn it to CD or DVD.

Even though the image has undergone compression, the latter option will no doubt involve multiple discs; sensibly, the software enables you to split the image accordingly.

After O&O DiskImage is installed you're faced with a simple-looking interface. Under the slightly patronising banner of "Which task would you like to run?" are the options available to you: image creation; restoring an image; mounting the image as a browsable drive; and writing the image to disc.

Choosing to create an image is simple enough. What's annoying is the time it takes to complete this process: well over an hour in the case of our PC, which contained 30GB of data.

Taxing process

Contrary to O&O's claims that "you can continue working during the entire imaging procedure", any attempt to use the PC for anything more taxing than watching the screensaver kick into life proved futile. It's best to create the initial image when you've planned something that doesn't involve touching the keyboard.

Once the imaging process has finished the program verifies it - a reassuring touch - and then it's up to you as to what to do with it. For example, you can mount the image file as a drive, which enables you to browse it, Windows Explorer-style, or protect it with up to 256-bit AES encryption.

Restoring an image on to your PC is straightforward: pick a drive and you're off. Here, you can also choose to write over unused drive sectors, for that whiter-than-white finish to your C drive.

Incremental imaging

Now that the base image has been created you can move on to incremental imaging. As you'd expect, this is a much quicker process because only changes to your system are accounted for. You can also merge several incremental images, which cuts back on wasted hard disk space.

One final noteworthy feature is that if your PC refuses to boot, you can use the installation disc to get things working again. It contains Windows PE (preinstallation environment), which will enable you to start the program and then access your most recent image.

Apart from a few stuttering dialogs while images were mounted, O&O DiskImage gets the job done without much fuss and bother. It's a streamlined package, which is a kinder way of saying that it's not loaded with features, and it's not the fastest kid on the block, either. However, used as insurance against an array of worst-case PC scenarios, O&O DiskImage is a policy that's worth taking out.