Using Extended Bios with Window XP

I have a laptop with Windows 7, which doesn't support booting from a USB port. I have installed Easybcd beta build 94 on this laptop and using the Extended Bios option.

I connected a bootable HD with Windows XP to a USB port. When I try booting from the USB, I can see Windows XP loading, I can even see the Windows XP logo, but soon after I get a blue screen saying check for viruses or run CHECKDISK and the laptop reboots again almost immediately.

When I use the external HD with Windows XP as an internal HD, the laptop works perfectly. Actually, I've been using the external HD with Windows XP as an internal HD in this laptop for few years, now I would like to use it as an external HD using a USB port. I'm using a "Y" USB cable to give to the external HD more power, in case it needs it for booting.

Do I need to do something else to make it work?

Last edited:


Mostly Harmless
Staff member
Hi Jorge,

So long as Windows XP begins to boot, that means that EasyBCD's extended BIOS has done it's job... but obviously you knew that.

What remains is the fact that it's extremely difficult to boot Windows XP and up from an external device for "piracy-related" reasons.

With Windows Vista and up, Microsoft has explicitly disallowed the booting, with checks during both setup and boot times. With Windows XP, it is simply an unsupported case - but it's not easy to get it working.

What happens is that as soon as Windows XP's own drivers for USB support kick in, the device is viewed as an external media. It no longer goes through EasyBCD's extended BIOS to access it, and instead uses it's own USB stack... which causes it to BSOD with an an inaccessible boot device (or similar) error.
Thanks a lot for your very quick reply. Am I right to say the problem is due the USB drivers from my external USB Windows XP? If this is the case, do you think that disabling the USB controllers from the external USB drive will help?
Many thanks,