тестую
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINDOW S
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Windo ws XP Media Center Edition" /noexecute=optin /fastdetect
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(2)\WINDOW S
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Windo ws Vista" /noexecute=optin /fastdetect

толком не знаю... .