HI suatatan,
Welcome to the HP Forums!
I would like to take a moment and thank you for using the forum, it is a great place to find answers.
For you to have the best experience in the HP forum, I would like to direct your attention to the HP Forums Guide First Time Here? Learn How to Post and More.
I understand that your computer is automatically shutting down. You took it to a repair center to have this resolved, but it was not. Here is a link to Troubleshooting an Overheating and Auto Shutdown Issue. You can also run The HP Support Assistant to help with updates and resolving issues. I would also suggest running a hardware test, just to rule it out. Testing for Hardware Failures (Windows 7, Vista), the steps will be the same for XP.