It should Be covered. A friend of mine had a dell pc that stopped working after an electrical storm power outage. They called dell and dell asked if it was damaged by an electrical storm, she told dell probally. Dell told her it was not covered under warranty since the power storm damaged it. I called Dell back for her and told dell the Mother Board will not power on. Dell asked me the same question, My answer: "It is summer time, we have electrical storms almost everday, but there is no way for us to determine if the electrical Storm was the cause of the bad/faulty Motherboard." Dell overnighted her a replacement Mother board free of charge.
It is all in the wording of how you tell the Manufacture why your mother board is not working. Try telling the Manufacture that your PC will not boot, sometimes it is best to play dumb, and let them trouble shoot it is a bad motherboard, not you telling them it is bad.
