SCSI Windows NT from vmware to virtualbox

We are trying to virtualize an old Windows NT 4.0 server in a bad shape. We've managed to create an vmdk image using vmware converter coldclone boot cd and we can successfully run it on vmware workstation which works flawlessly but we want to migrate it to Virtualbox.

When the VM is created as IDE or SATA Controler it loads up to a point and then gets stuck on blue screen STOP: 0x0000007B INNACESSIBLE_BOOT_DEVICE and loads of text about .sys files.

If we change the the controllers to SCSI or SAS it just gives us a black screen "Missing Operating System" We've tried switch on/off IO APIC and Enable VT-x/AMD-v also switched between lsilogic and buslogic Always getting the same results.

Any help will be higly appreciated, many thanks in advance! :-)

Windows NT (<5.0) uses a Static HAL configuration, meaning it doesn't support changing the storage driver associated with the boot device. It may be possible to hack the registry into working with a new driver, but at this point I honestly don't remember if that's possible (you are working with an ancient OS).

The "easy" fix is to ensure you're booting from a device that uses the same driver as the previous "hardware" (even if that hardware is virtualized).