Acer randomly shuts down

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http://askubuntu.com – I just bought an Acer Aspire One 756 in Romania with Ubuntu pre-installed, and i choose to reinstall ubuntu for english language and my correct keyboard layout. but now it randomly shuts down. I don't know what information would be helpful for you to find out the problem, so just give me a command line and i will add it to the question (HowTos)