From what I am reading here there is a real reason why this will never work.
ingenium, and arnuschky
If you have installed the Windows OS in VBox with the VT-x/AMD-v switch off (as the logs show) and then turn it on that will not work.
The OS in Windows case will not have the proper Kernel. It is one or the other. The only way to change the kernel (As far as I know) is to reinstall.
Of course I could be misreading here if so please disregard and I will go back to sleep now.
It's actually never worked for me in Virtualbox with Windows, though I've only tried the one Windows VM. Linux VMs in Virtualbox seem to work fine with VT-x enabled. So it may be the kernel issue...can you post a link to other people with this problem? I'm wondering if I can just drop in a replacement kernel for it instead of reinstalling.
A fresh install of Windows XP works with VT-x enabled.
The new copy was SP2, whereas the VM is SP3. I upgraded the new copy to SP3 and got it fully patched. It still worked, and the kernel modification dates are the same.
When I did an md5sum on the kernels, both were the same. So it's NOT the kernel.
More testing revealed that the original VM would boot into safemode with VT-x enabled. I created a new user, and the VM hangs when I login with either my old username or the new one. Any suggestions short of starting fresh?
EDIT: Uninstalling guest additions in the original VM fixed the problem. After re-installing it no longer hung. So something with guest additions was the culprit.
