virtualbox.org

I just installed VirtualBox2.2.0 on my Ubuntu8.10 64-bit version and when I go to make a new virtual machine or edit an existing one, there is no option under the operating system version to select 64-bit. I've installed from the .deb package and I've also tried from the .run file as well. VT-x/AMD-V are enable by default though, so I don't know what is going on. I was talking on the ubuntuforums and it is believed that this is a possible bug because they were having the same issue as well. They suggested I report this as a bug, but before that, I wanted to ask on here and see if anyone could possibly help out.

If VB won't give you a 64 bit option, you don't have VT-x/AMD-v turned on in your BIOS. Check that. See the manual and VirtualBox FAQ for what you need for 64 bit guests.

Not all 64-bit CPUs support VT-x/AMD-v either, so that might not necessarily help