after 6 months and 2 returns to RMA finally found the answer here:!!!!!
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If your laptop is overheating during use, see the [https://www.ifixit.com/Wiki/Acer_Aspire_5253_Is_Overheating|Acer Aspire 5253 Is Overheating problem page] for possible causes and solutions.
I was surprised no one had report this issue before, it was happening with external monitor connected to laptop..
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As the link above indicates, you must unlug any external monitor connected to laptop during boot, and plug again after boot... very strange issue!!!!
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As the link above indicates, you must unlug any external monitor connected to the laptop during boot, and plug again after boot... a very strange issue!!!!
finally just found the answer here!!!!!
http://community.acer.com/t5/V-and-VN-Series/Fan-randomly-not-working-Acer-Nitro/m-p/400188/highlight/false#M6793