System wont shutdown

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I am a newbie
And use Linux mint XFCE 12 as a home theatre PC (with XBMC and my phone as a remote)
All works well with one exception, the system wont shutdown, this has never worked under Xfce mint.

I've tried other Linux version and those could shutdown, (mandriva debian etc), so linux should be able to shut it down.
My system is brand new its an asrock 350M1 with 4 GB of memmory and runs on a 32GB SSD drive.
( i didnt use an old motherboard for this, i bought a new miniPC board )

I am new to linux so i dont know where the look for or what to change in the system to resolve this
Can someone help me ?

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solved
through a chat session, the packag manager has an option with updatable kernel modules
system>synaptic package manager > status > select upgradeable
there i upgraded linux header files and core files