My pc does not show Bios post message .and when i using my pc suddenly it stop processing and shutdown. what i do now?.

if your PC is booting into Windows but you don't see BIOS/POST messages, it may just be happening too fast. but you can get into Windows? Are there any Errors in the Application or System logs? if you've got a software problem, you'll usually see an entry here with the name of the offending software. then you can just uninstall or repair the installation of that software. if this is a hardware problem that randomly started occurring, the HW could be dying. if this is a hardware problem that started occurring after you changed something, you should describe what you changed.