Now if you had a whole System Image from prior to the problem, you simply insert your Rescue Boot Disk you created for your Imaging app, connect whatever media you have used to store the Image (I use an Ext HD) and restore the Image. In this situation the System Restore points are on the same partition as the OS. If this partition is badly corrupted you may not have access to restore points.
This is one reason why Images cannot be stored on the same partition as the OS. They can be saved in a different partition or drive, but if in a different partition and the whole drive dies, your Image is also lost. That's why storing Images off PC is best.
Both System Restore and Imaging have there place. System Restore quickly fixes many system files if something unexpected happens, but when real disaster strikes Imaging is the savior.