Tools like Acronis promise to enable you to restore the PC to a running state in no time, because when your hardware is defect, you just replace it and restore the backup and everything's fine.
Except that you won't be able to activate your OEM licensed Windows on a new box. (Yes, if only the HD's toast, then you should be fine.)
Given that all home boxes I know are OEM licensed, and the DELL boxes at the office come with preinstalled Windows too, isn't such imaging backups a waste of backup space (after all, a PC image is much larger than just saving the user folder) that you then can't restore anyway when the wrong part of your PC goes bust?

slmgr.vbs -ipk your_serial_number_hereand activate it usingslmgr.vbs -ato(if I remember correctly). Here's the manual for that. Using this, the installation should have switched licenses. How legal is that is a question for a lawyer (but some EULAs may explicitly disallow that). With that taken into account, the full disk images aren't very interesting for OEM users. – AndrejaKo Jan 7 at 21:29