Cannot start installation or livecd in Virtualbox on my Lenovo Tablet 8(Windows 8.1)

[Patchie Patch]

hey, i have a "lenovo Thinkpad Tablet 8" with a Intel Atom, 2gb ram, 128gb SSD and win 8.1 pro.

I have installed Virtualbox and downloaded Android-x64 4.4r2 iso: http://sourceforge.net/projects/android-x86/files/Release%204.4/android-x86-4.4-r2.iso/download

I boot the VM, and it goes into the first menu, where i can choose to install or run live cd, but when i choose one of those 4 options, it just restarts

this is the menu i get into: 

This is the settings i have got in my virtualbox: 

any idea what can be wrong?