Final answer:
Turn off the computer immediately and unplug it to prevent further damage and reduce the risk of electrical injury or fire.
Step-by-step explanation:
If you see smoke and smell a strange odor coming from your computer, the most important action to take is to turn off the computer immediately and unplug it from the power source. This action helps to prevent further damage to the computer and reduces the risk of fire or electrical injury. Immediate action is crucial, even before contacting IT support or considering additional steps like evacuating the building, although depending on the severity of the smoke and the potential risk, those steps may become necessary shortly after.