virtualbox.org

on windows 8.1 host:
I tried to install debian 7.2 amd64 and 7.1 amd64, but process freezes after selected method of installation
in expert mode of installaion i get an error: why? i have core i3 3110M (with intel vt-x support and 64bit arch)

now i have to install x86 debian

Select the 64 bit version in the OS type of the VM, and that Virtualization is also enabled for that VM.
If that is not present, make sure VT-x is enabled in the BIOS and Hyper-V is not running.