Hi guys,
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FIXED (thanks to Shiitaki) by :
1) Removing CMOS battery and everything (except CPU ^^) from the MB
2) Waiting 2H
3) Plug CMOS battery, 24pin MB power cable to power supply, 1 RAM stick
4) LOOP: shutdown, unplug power cord, plug 1 item to MB, power on
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First, if this post...