PC: Device Does Not Boot but Fans Spin and Lights Turn On

Follow the below steps if the device does not boot, but the fans spin and status lights turn on. Most often, this is caused by a peripheral not connected securely.

Reseat the RAM

RAM is one of the biggest offenders for systems not booting. The following steps only work if your RAM is not soldered, meaning your device uses DIMM or SODIMM sticks of RAM. If you RAM is soldered continue to the next section.

1. Verify that the device is powered off and unplugged.
2. Pull all sticks of RAM and put them on a non-conductive surface, such as an anti-static bag.
3. Seat 1 stick of RAM.
4. Plug-in and power on the system to see if it boots.
5. Power off and unplug the device, then follow Steps 1 through 4 until all sticks of RAM have been installed or the system fails to boot.
   1. If one stick or more, but not all sticks, prevents the device from booting, then you mostly likely have a bad stick(s) of RAM. 
   2. If the system fails to boot with each stick of RAM, continue to the next section.

Ensure Wires/Cables Are Connected Securely

Cables that aren't securely seated in their slot can cause power instability in electronics, resulting in a failure to boot. This only works with devices that have peripheral wires/cables, if your device does not use peripheral wires/cables then proceed to the next section.

1. Verify that the device is powered off and unplugged.
2. Follow and check each wire or cable to ensure that it is securely seated.
3. When finished checking the seating, plug in and power on the device to test it.
4. If this does not fix the issue, proceed to the next step.

Drain the System of Power

Computing devices are comprised of hundreds of sub-controllers and processors. Each containing its own computing logic and possibly its own RAM. Just like Windows, the various controllers can become clogged with data. Resetting these requires a full system power drain. Follow the steps below to drain the system.

1. Verify the system is powered down and unplugged from the wall.
2. If the device has a built in battery, disconnect it.
3. Remove the CMOS battery.
4. Press and hold the power button for 30 seconds.
5. Insert the CMOS battery and reconnect the internal battery, if there is one.
6. Plug the device back in and attempt to power on the device.
7. If this does not fix the issue, proceed to the next step.

Replace CMOS Battery

CMOS is a critical component of computing. Known as complementary-symmetry metal-oxide-semiconductor, the CMOS is the brain of the BIOS and Motherboard. The CMOS is a set of computer components that control BIOS firmware, RAM and real-time clock. The CMOS battery powers the real-time clock and enables the BIOS to store changeable values in its RAM. Replacing an old or drained CMOS battery can fix a lot of intermittent system issues.

Check System Documentation for Troubleshooting Codes

If you are unable to fix the boot failure, look for a diagnostic code on your device. Laptops and desktops generally have a flashing power code. For instance, the power button may flash quickly 3 times, then pause and flash quickly 4 times, this would be considered a 3,4 error code. Research these codes on the internet can give you an answer to what the issue is.

If your device is custom built, look for a diagnostic light on the motherboard, the flashing cadence and color of the light can indicate what the issue is. Research the color and flash code on the internet for better idea of what is wrong with the device.