The 07B is an inaccessible boot volume, possibly caused by virus or messed up file system, or the lack of controller driver
in XP installer for your HD which theog covers above.
Try running chkdsk /r from booted Windows 7 DVD repair console Command Line or Windows 7, then try XP install again.
Next backup your files and a Windows 7 System image then deep clean the HD to eliminate any virus, by running these commands:
SELECT DISK # (replace # with target HD #)
This zeroes the HD for deepest clean but takes a long time on large HD's.
(Which Greg are you referring to in your OP, and what advice?)