If the drive is not recognized by the system

[Alexey V. Gubin]

There are three most common failure types described as "drive not recognized".

Drive is physically OK, but the partition table is damaged and no volumes can be mounted. This creates a perception of a "not recognized" drive. However, the drive is listed as attached to the system in BIOS setup and Windows Device Manager applet. In this case, the data recovery is performed as usual (e.g. as outlined here (http://www.z-a-recovery.com/unformat-tutorial.htm)).
The drive is a regular IDE hard drive (either 2.5" or 3.5") inside the USB or Firewire enclosure, and the enclosure had failed. This is typically solved by removing the drive from the failed enclosure and attaching the drive directly to the motherboard IDE port. Depening on the exact failure mode, you may regain access to data immediately; otherwise, a typical recovery run may be required to recover data off the drive.
The drive is physically damaged to the point BIOS does not recognize it. Such a cases are beyond the capability of the software repair. ZAR cannot be of any use with such drives.

[k4tertots]

when i follow the tutorial, and i click on the physical disk and hit next, it starts to scan instead of going to step 6. is it suppose to do that?

[Alexey V. Gubin]

On a removable device, in the image recovery mode, it is possible that it will start scan automatically (if it senses there can only be one volume on the disk). This "auto start" does not happen often and (by itself) does not indicate a problem.