Abstract: A multi-purpose scanner that can be integrated into a computer. In one embodiment, the multi-purpose scanner functions as a desktop scanner. It includes a scanning engine and an external housing. The external housing substantially encapsulates the scanning engine to reduce electromagnetic interference to the scanning engine. In another embodiment, the multi-purpose scanner scans with scanning engine mechanically attached to the computer. The scanning engine includes an internal body, a chassis and a positioning assembly. The chassis holds the internal body, and the assembly moves the internal body relative to the chassis. In this embodiment, the scanner extends a part of the internal body out of the chassis in order to scan a medium. In a third embodiment, the multi-purpose scanner functions as a handheld scanner. The scanning engine includes a front-panel unit that is releasably attached to an engine unit.