Alternatively, one boots with the XP install disc and select the Recovery console. Temporarily remove the system, hidden, and read-only flags from boot.ini. Delete boot.ini. Run bootcfg /rebuild to create a new boot.ini file, and scan drives for Windows installations to add to the boot loader.

One should be able to remove all the attributes at once using the command attirb -h -r -s c:\boot.ini. Also, instead of deleting it, I would rename it, such as to bootini.old, until the system is working properly.

Resources:

• Spotmau check boot path page: http://www.spotmausupport.com/check-boot-path/
• Intuitively fixing BootCamp (not recommended!): http://blog.blackrobes.net/2009/06/bootcampin-the-night-away/