I have seen similar issues on newer Dell PCS. Open up the case and look at the motherboard. You will see several smallish capacitors (black tubes with a silver top). Visually, check to see that the silver tops are all flat. If they are bulged upward, or leaking, the motherboard needs replacing.
Also, check that all of the small wires coming from the front of the computer are attached snugly on the motherboard.
Good Luck