I have an Acer laptop, aspire 5100. i have just installed new windows for professional XP pro yesterday, but since i started installing new windows .. it keeps turning off by itself. it still keeps turning off even after my installation of windows and other software. and it is not a heat problem .. i have checked. so any suggetion what might cause it and what can i do . ?? .. really need it .. my classes are starting on 25th .. thanks ..