- Check all your media slots have nothing in them, i.e. USB, CD/DVD drive and flash drives etc.
- Try a start with AC cord only, and no battery, then no AC with battery only.
- Remove the battery and AC cord. Remove the bottom cover/covers of your laptop and make sure the cooling path is not full of dust. Check the heat sink on the CPU is not loose.
- Remove and reseat your RAM modules.
- Hold down your power button for 1 minute (Battery and AC still disconnected).
- Remove your HD, and try starting your laptop. If it goes through the POST, and then a black screen appears with the message Operating System Not Found, and remains at this screen, then your HD is faulty. Replace with new HD. If that didn’t work then let’s move on.
- You need to identify what one is faulty. Remove all the RAM. Take one stick at a time, and swap it around the RAM slots to see if the laptop will start. You have now identified the good RAM. If each stick produces the fault, then you may have two sticks of bad RAM or a bad RAM slot. Borrow or buy known working RAM.
- Make sure your CPU is seated correctly, if that didn’t work, borrow or buy new/secondhand known working CPU.
- Next is the GPU. This is not so easy, as most are integrated onto the motherboard. If yours is a high end laptop then you may have a removable graphics card. Remove and reseat this, if that did not work, borrow or buy known working GPU.