A fairly familiar form of laptop boot problems is when the unit powers up when switched on, after which it unceremoniously shuts down after the fan and the CD-ROM drive has whirred to life for a few seconds. No image is displayed on the screen at all.
The problem is when the laptop is no longer covered by warranty. If this is the case, you won’t lose anything by opening up the case and having a look around provided that you don’t touch anything you aren’t absolutely sure about. Sometimes the problem could be fixed by simply reseating the cable to the hard disk. While you are looking around, you may also want to check for other cables that appear to be out of place. Keep in mind that you will void your warranty if it is still active by opening up your laptop.
You also have to make sure that what you are experiencing are indeed laptop boot problems and not issues with the video card. Connect an external monitor to your laptop and see if an image shows up. If it does, there is probably something wrong with your video card.
More worrying are laptop boot problems that have to do with a damaged motherboard or CPU. This will likely mean a complicated and expensive replacement procedure, and depending on how old your laptop is, it may not be a worthwhile course of action to take at all.
In a small number of cases, laptop boot problems can be caused by nothing more than a dead battery. Many newer laptops do not exhibit this behavior although if your laptop is an older model, it may be a good idea to check if a new battery will make the problem disappear.