virtualbox.org

I have searched the forums, and I believe I have tried everything I've found, and am still having a problem:

I have Win XP 32-bit, and I want to install Win 7 Pro 64-bit as a guest. Every time I start the Win 7 VM, I get an error stating "VT-x/AMD-V hardware acceleration has been enabled, but is not operational. Your 64-bit guest will fail to detect a 64-bit CPU and will not be able to boot."

I have enabled Intel virtualization in the BIOS. I've disabled virtualization, unplugged the computer for 2 minutes, enabled virtualization, unplugged computer for 5 minutes, then started the computer. No joy. I've removed VB, restarted, reinstalled VB, removed the old Win 7 machine, made a new Win 7 machine; no joy.

I have a Dell Optiplex 755 with an E8300 Intel processor (http://ark.intel.com/Product.aspx?id=35070). Intel's site shows it is both Intel 64 and VT-x capable. I have updated the BIOS to the latest version (A15) prior to most of these troubleshooting steps.

What else should I be looking for or trying as a solution?

Attach the VBox.log file of such a session. That will show exactly why VT-x isn't enabled.

SOLVED:

Disabled "Trusted Execution" in the Performance section of the BIOS, per a post I found on Dell's forums.

(http://en.community.dell.com/forums/p/1 ... x#19259528)

(Thanks anyway, sandervl!)