naz, the possibilities are to numerous at this time to give you a definite answer. Start systematically to narrow it down. Make sure that your power supply is working. Take a multimeter and make sure that the output voltage is correct. I believe it to be 19volts for your mini. If you have power from your AC adapter, remove the adapter from the computer, remove the battery and remove the memory module. Leave it out for a while. Then replace the memory and the AC adapter and see if it starts. Also replace the battery after. If it still does not show any sign of life it is time to take it apart and visually inspect for any burned capacitors, you will recognize those by a bulging top. Also make sure that you clean the fan and the air vents and make sure that your computer has good airflow. The service manual is available right here http://h10032.www1.hp.com/ctg/Manual/c01683469.pdf