Windows' backup is great for backing up data files, but after a hard disk crash, you may not be able to get your copied version of Windows up and running. That's because Backup may not have copied hidden or system files that Windows needs to run and the settings in your msdos.sys file may need to be altered. Also, corrupted files may slip into your Windows backup long before you see their effects -- which may range from strange mouse behaviour to system crashes.

None of the above is a problem if you create an exact image of your hard disk. You can do this with an imaging program such as PowerQuest's $99 Drive Image 2. This powerful utility can copy and compress your entire drive -- system files, hidden files, your disk's file allocation table, and everything else -- into a single file that can be stored on your second hard disk and restored at will.

My advice is to get PowerQuest's PartitionMagic and create three partitions on your hard disk. Install Windows into partition C:, your apps in D:, and your data in E:. Now you can make images of each partition. Subsequently, whenever Windows starts misbehaving and you can't isolate the trouble, you can restore your original Windows partition. Just remember to update the images after you add any new hardware or software and confirm that your system is functioning properly.