Re: system freezes randomly and for no apparent reason
Can you pin point any change that happened when it occured ?
Do you still get the same issue when running from a live cd/usb ?
As you reinstalled xubuntu and still have the issue, i would suspect/eliminate hardware in the first instance.
What hardware tests have you run ?
EDIT: Can you shutdown by getting to a console ?
Can you shutdown using the magic key combination (alt + sysreq .....) ?
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