Asus A6000 power shutdown

Shutdown can be caused by several things.

Easiest, operating system corruption...

Try starting up your laptop, and hit the "setup" key, usually F2 or Del... once there, leave it running for 15 to 20 minutes. If it stays up, then you have a problem with the OS.

If it dies again, you may have issues with cooling of the chipset or CPU. Make sure your system gets sufficient air cooling. some systems have the ability in the setup menu to monitor the CPU core temps and voltages. Watch these also.

Last, but not least, you have a power supply problem. This too will cause a shutdown...  Hope this helps...