virtualbox.org

I have windows 8 64 bits, and have several 64 bits guests that i used to run.
After upgrade virtual box, i cant access anymore.
Get VT-x/AMD-v not avaliable.
My processor is an i7 3770K, is enable virtualization on bios.
Cant install new guest either.
My VirtualBox version is 4.2.18
Any tips?

Find out.
Problem is i installed Hyper-V.
Uninstaled and worked again.