What laptop do you have, and how long have you had it?
There's a possibility that it's overheating. What are your system temperatures when you boot up? Use a freeware program like CoreTemp
to monitor your system temperatures. Your BIOS may also provide you info about your system temperatures. Also, does it get abnormally loud when you're booted in the OS?
Whether you can take out your hard drive before servicing depends on whether the service provider permits you to. Most permit it, especially if it's being serviced by the notebook manufacturer since they have the necessary images to diagnose hardware problems without the customer's hard drive. However, 3rd party repairers may not allow it.