will win 7 laptop boot from ext XP drive?

I'd like to boot a Win 7 laptop from an external hard drive with XP and software installed. Probably use a USB port input from the drive through an adapter. Is it possible to boot XP that way and read and write personal files on the drive? The drive is eSATA and is Windows 7 compatible.

You can boot from eSATA but, I don't think you can from USB. You can read files from the drive with USB, but I don't believe it will boot.

EDIT: I just tried to boot from a USB external dock. It wouldn't do it. I boot frequently from eSATA.

There is a way, but it's very unconventional. I don't recommend you try it unless you're very comfortable with this sort of thing. Anyway, here's the page you're looking for: https://sites.google.com/a/rmprepusb.com/www/tutorials/win7onusb

Since it's very unusual we (meaning me, since I doubt anyone else has experience doing this) probably won't be able to help you much if you encounter errors. So like I said, proceed at your own risk.

EDIT: sorry I misread your post. I thought you were trying to boot Win 7 from the drive. That page might still work for you, but I don't know. Again, proceed at your own risk. I'd recommend making sure any important files on your external drive are backed up before trying this because this process will wipe everything off your external drive.

Thanks, essenbe and Slammer. I had a desktop with an external eSATA port but would have to find a laptop with one - don't remember seeing any lately - most of them have USB.

Can you still get into BIOS with F12, delete or some other key on most laptops or has the ability to change the system config at that level been taken away by the manufacturers?

You can usually get into bios, but many of the options are not there. But, usually sata configuration and boot order will probably be there. Also, many of the newer laptops do have esata ports. Just look for that option when shopping. Aside from being able to boot from it, esata is a good option to have for several other reasons.