>I want to know how long my PC working till las reboot
I don't know of any special Windows API function - I hardly know this topic, but an option might exist.
However, you could create a file, as part of the startup procedure (in Autoexec.bat, through the "Startup" group in the Startup menu, through the Windows task scheduler, ...), and check the datetime of the created file.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)
