I think I have an easy fix...
Open "My Computer" and click on the "Organize" tab, select "Folder and search options". When the "Folder option" window pops up click on the "View" tab, and make sure to
"Show hidden files, folders etc...)"
UNCHECK "Hide protected operating system files" AND "Hide extensions for known file types".
Next, go into you C: drive, and find the file boot.ini and... well, I made a folder called "Moved boot ini here" and jammed it in it... I rebooted, and yay, multi-boot option gone!
You can also mess with the permissions (so you can save it after editing) and put a ; (semi colon) in front of EACH line. Adding the ; makes that specific command line not work...
;Warning: Boot.ini is used on Windows XP and earlier operating systems.
;Warning: Use BCDEDIT.exe to modify Windows Vista boot options.
;c:\CMDCONS\BOOTSECT.DAT="Microsoft Windows Recovery Console" /CMDCONS
Hope this helps someone