Can not install other system after pre-installed Win8 how to solve

Start today with a t430s, pre-installed WIN8 X64 system. Because some software and systems are incompatible, but only to switch to WIN7. Oddly, when I use the Windows PE boot disk, I try to get into the PE tool but I can't get it in anyway, and so does the USB disk version of Windows PE. Have not encountered this problem before, the preliminary estimate of the small series should be caused by the security settings.

The boot into the BIOS, modify the following options, the problem is resolved, the steps are as follows:

1, reboot the machine, into the BIOS

2, enter the security->secure boot option, set its value to disabled.

3. Enter the startup-uefi/legacy boot option to change the value of the uefi/legacy boot option to both, and then select the Uefi/legacy boot priority value as UEFI.

Press F10 to save and restart the computer, plug in the U disk version of Pe,ok. We can finally get into the!~.

This is because the BIOS for the WIN8 notebook is now different from what it used to be.

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