Since Vista, Windows stores the boot menu in a Boot Configuration Data store (BCD). I took a look at mine today, and here's the entry for the one and only Win7 instance:
Windows Boot Loader
-------------------
identifier {current}
device partition=C:
path \Windows\system32\winload.exe
description Windows 7
locale en-US
inherit {bootloadersettings}
recoverysequence {89491629-36d4-11df-938c-f89ebe5d401b}
recoveryenabled Yes
osdevice partition=C:
systemroot \Windows
resumeobject {89491621-36d4-11df-938c-f89ebe5d401b}
nx OptIn
The ARC paths of boot.ini are gone, it seems - this boot entry has a C:
to identify the drive to load Win7 from. But aren't drive letters arbitrary in Windows? How does it know what physical drive and partition corresponds to C without looking at the registry first?