Numeric error code 1802 prevents system from booting. Unauthorized network card is plugged in. Network cards distributed by Lenovo have a unique Subsystem Vendor ID / Subsystem Identifier (SVID/SSID) which is checked at every boot. If the SVID/SSID doesn't match, then error code 1802 is displayed. The purpose of this check is to guarantee that both network cards and computer systems distributed by Lenovo are used in card/antenna pairs which have been certified by regulatory bodies like the FCC. Consequently, there may be both Lenovo versions and Generic versions of a vendor's network card, and even though they are electrically similar, they are registered as different cards by the regulatory body.
The following systems maybe affected by this symptom:
If you have installed a network card obtained from a non-Lenovo source, then turn off the system and remove the card.