Today I installed on my Desktop Windows Server 2003 R2 (WS2003) in D:\; The machine has in C:\ Windows Vista Beta 2 working. After the base installation of WS2003, machine restarted and that’s it. It complained about a bad boot partition and refused to proceed further. There was no way to continue WS2003 installation (or) get back to Windows Vista. Then I resorted to booting the machine with Windows Vista CD, went into recovery mode. In recovery mode after trying auto-fix options, I went to command-prompt. Windows Vista Recovery mode command prompt shows up as X:\ and has the default recovery utilities loaded there. One of the utilities I found was BootRec.Exe in X:\Windows\System32. Used the tool to rewrite the partition boot record and the MBR (Master Boot Record) by following commands:
X:\Windows\System32\BootRec.Exe /fixboot X:\Windows\System32\BootRec.Exe /fixmbr
After this, I restarted the machine. Everything worked well I got Windows Vista booting, but no way to reach WS2003. I tried editing c:\boot.ini, no effect. Doing some research I realized Windows Vista has a new Boot Configuration Manager, Boot Loader – Boot.ini has no effect on Vista. BCD (Boot Configuration Data) Store in Windows Vista has replaced Boot.ini and there is no GUI to do changes to it. There is a command-line utility “BCDEDIT.EXE” that can be used to view, modify boot options. After reading about BCDEdit, I realized it was not that easy to understand at first try and I need to do the serious reading before I can use it. So I searched for more information on BCD and then came across VistaBootPro. VistaBootPro is a 3rd Party utility that gives an easy GUI to add boot partitions and do pretty much everything that BCDEdit.Exe can do. After installing the tool, it took me few seconds to add my D:\ (Windows Server 2003 Partition) into the boot sequence. After restart got the Vista Boot Menu showing both Windows Vista and Windows Server 2003 boot options.
If you want to avoid all this, first install the old version of Windows (Windows XP, Windows Server 2003, etc.) then install Windows Vista.
Update Nov 2007: I found this Technet article detailing on how to do common tasks in BCD.