What to do when there is smoke billowing from the server board/system?

No evidence of boot (no graphics displayed), just smoke billowing from the server.

Smoke coming out of a system is rare; yet, when it happens, immediate user action is expected.  Remove the power cord(s), step away in order to avoid inhaling foreign substances, and contact your system administrator/integrator.

Although “the limited warranty doesn't cover damage to the product due to external causes” (qtd. here), if, after careful inspection, in the event a physical damage is determined, contact Intel Customer Support with the following information for diagnosis:
1. Pictures of the physical damage is desired, if possible.
2. Brief description as to how the system is integrated, hardware-wise.
3. Details as to what might have caused the scenario.
4. Identifying numbers of the server system.

Cause: Possible wrong hardware integration