Aspire ES 15 install windows 7

Hi all,

I have to install windows 7 on Aspire ES 15 (ES1-533-C4BY) and there's some problems.

Bios version is V1.04. So, I disabled the secure Boot.

Legacy boot can't be selected in boot mode (UEFI only) (is there a hidden way to enable this option ?).

And when I try to install windows from USB key, booting on the key works correctly, Black screen is displayed with Windows picture ... and it freezes.

Have you got some idea ?

Many Thanks

Fred