First, XP will not boot from from an external drive. That is a feature of
XP. An excpetion might be an eSATA drive, which appears to XP as if it were
an internal drive of type SCSI.
As for "Image for Windows", why not contact the support website and loom for
information, such as FAQs, how-tos, etc?
For example, see page 58 of the on-line manual:
http://www.terabyteunlimited.com/downloads/ifw_en_manual.pdf
In the event that you failed to make a Bart's bootable CD before the current
crisis, be aware that a Bart's CD made on one computer may work on other
computers. However, if you have an SATA-type hard drive you may need to
provide Bart's (really a slim XP) with drivers for your motherboard's SATA
controllers, and they must be on a floppy disk. It is also possible to
merge the drivers into the Bart's CD, although I have never bothered
learning how to do that, since my PC still has a floppy drive. Another
possibility on modern PCs is to change a BIOS setting to treat the SATA
drive as if it were plain ATA (also called IDE). If your PC has such an
option, it will eliminate the need for SATA drivers, but file trasnfers will
be slower. Still, the real limitaion on the speed of recovery will be USB
2.0. After the recovery, you can revert the BIOS settings back to SATA.