I've just Installed Ubuntu 12.10. When asked to remove dvd to restart there was no boot option menu and PC started to load windows.
Checkdisk ran and displayed multiple messages, eg.
Deleting orphan file record segment 123416.
In Windows XP my C:\ was reduced by the amount of space allocated to ubuntu partitions.
I accessed boot menu and there was only the option for Normal windows start up and windows recovery start up.