M4600 Bios Post freezing

I have dell precision m4600 bios version a19 and it's worked fine but yesterday suddenly when i was trying to reinstall windows10 its freezed in post (dell logo) and i tried this:

changing ram slot (i have 2*8gb) with the under the keyboard and in the back and tested with each of them

Take off every usb and another thing connected+ disconnecting every cable is under the keyboard+ pulling out the battery and bios battery 

I left it for 24h without bios battery and battery and ac adapter 

I pulled in and out everything 

Changing disk with 3 another disk

Still not working and just one thing is keyboard working for something around 2 second and i can see the yellow message preparing to enter setup after pressing f2 ( i tried ctrl+esc , ctrl+alt+esc and not worked)

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I appreciate all help in advance.