Lifebook E751 and Windows 10 special keys

[dng1961@hotmail.com]

Hello everyone !
I am the owner of a Lifebook E751 and I have some questions:
I am considering to move to Windows 10 but after making a test installation of Windows 10,
found out that the special keys and many of the function keys other than F1,F2, etc are not working.
Also the serial port is marked as yellow in the device manager
Has anyone any kind of suggestions ?

The other question is related to the max ram the Lifebook E751 can handle.
According to Intel, the chip set can handle a max of 16Gb of ram, while Fujitsu claims that the notebook can handle a max 8Gb of ram.
Any experiences ?

Kind regards to all
Dionisios