Hi,
Before going any further, please check your BIOS setting first to see if there is any setting for two hard disks' boot sequence. If possible, it is also better to contact manufacturer of the motherboard for further assistance.
According to your problem description, I suppose that you should remove the default active hard drive containing the Boot Configuration Data from the computer, which makes the system unable to startup properly.
On our side, please perform the following steps to repair the Windows Vista boot loader.
Rebuild BCD
1. Put the Windows Vista installation disc in the disc drive, and then start the computer.
2. Press a key when the message indicating "Press any key to boot from CD or DVD …". appears.
3. Select a language, a time, a currency, and a keyboard or another input method, and then click Next.
4. Click Repair your computer.
5. (Click the operating system that you want to repair), and then click Next.
6. In the System Recovery Options dialog box, click Command Prompt.
7. Type BOOTREC /FIXMBR, and then press ENTER.
8. Type BOOTREC /FIXBOOT, and then press ENTER.
9. Type BOOTREC /REBUILDBCD, and then press ENTER.
Startup Repair from the Windows Recovery Environment (WinRE)
1. Insert the Windows Vista installation disc into the disc drive, and then start the computer.
2. Press a key when the message indicating "Press any key to boot from CD or DVD …". appears.
3. Select a language, a time and currency, and a keyboard or input method, and then click Next.
4. Click Repair your computer.
5. In the System Recovery Options dialog box, choose the drive of your Windows installation and click Next.
6. At the System Recovery Options Dialog Box, click on Repair your computer.
7. (Click the operating system that you want to repair), and then click Next.
8. In the System Recovery Options dialog box, click Startup Repair.
If all the above instructions do not work, I would like to recommend that you clean install the system.
Hope it helps!
