neviem co nazyvas "zavadec", windows nikdy neprepise bootsektor druhemu OS, teda pokial ho neinstalujes na tu istu particiu, ostatne je tu nepisem nejake teoreticke zvasty, mam to odkusane, na internete je o tom tiez niekolko clankov napr: Understanding the Boot Process and NTLDR

jednoduchy priklad:

[Boot Loader]
Timeout=5
Default=multi(0)disk(0)rdisk(0)partition(4)\WINNT
[Operating Systems]
multi(0)disk(0)rdisk(0)partition(4)\WINNT="Microso ft Windows 2000 Professional" /fastdetect
C:\BOOTSECT.DOS ="MS-DOS (Legacy Support)"
C:\debian.mbr = "Debian GNU/Linux"