Hey all thanks for reading.

So last week my BIOS started warning me with the S.M.A.R.T. algorithm that my HDD status was BAD and said to backup and replace. So I've sent it in as an RMA to newegg. Meanwhile I'm without my desktop so I figure hey why not try and boot XP on my external HDD for fun and to learn something. I'd always heard it was impossible, but over the months I've seen articles pop up here and there saying "Boot XP from your usb key..." never looked into it really until now. Soooo, I looked around and found this guide:

http://www.ngine.de/index.jsp?pageid=4176

In short you edit the ISO file of the windows install cd so the USB controllers are handled appropriately on bootup and don't terminate the connection with the USB HDD. I did all the editing successfully I believe, but here is the problem. I don't have an application that can edit ISO files greater than 300mb, so i had to extract the ISO and edit the files there so I used WinImage to save the boot sector as an image, then used CDBurnerXP Pro to make a new iso with the old boot image and the edited files. It took a few tries to get a CD to even boot, but I finally did after some NTLDR errors and such. Now here is the problem. After the cd boot loads all the drivers and is about to begin the actual windows install I get this blue screen error:

UNMOUNTABLE_BOOT_VOLUME

...

Technical Info:
STOP: 0x000000ED (0x89B11030, 0xC0000102, 0x00000000, 0x00000000)

So now for the actual questions:

1.) Is there a better way to boot windows from an USB HDD?
2.) What is the most likely cause of the unmountable error? (I had big problems with getting it to even want to boot, possible problem still with the boot sector OR did my file editing corrupt something and that's why windows won't make it into the actual install?)

System specs:
USB HDD Seagate FreeAgent 250GB external
Windows XP Professional
Asus P5DL2 Mobo w/ AMI BIOS


Any help would be appreciated. Thanks for taking the time to read over this lengthy post.

Cya!