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I have 2 hard disk, one with one partition with OS, and the other with 2 partitions, one with OS and the other one whithout.

I want to be able to decide which OS I want to load each time I boot the computer. Of course, I can change BIOS' configuration and modify the boot order, but I don't want to do that each time.

Edit: Both OS are Windows XP

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Please specify the two OS's, that'll affect a few options. Thanks! – nerdwaller Jan 11 '13 at 18:38
@nerdwaller Good point, I thought I had said that both are Win XP – Oriol Jan 11 '13 at 18:44
Uhm, typically, I think it's supposed to appear on its own. Well, for the short while I had both Windows 7 and Windows 8, I did get the choice. But in the even that it doesn't come on its own, are these links useful?…… – Ariane Jan 11 '13 at 18:44
You need to read up on how to install a "bootloader" for windows. – terdon Jan 11 '13 at 18:46
up vote 4 down vote accepted

There are several layers where you can act.

Beware, however, that all these options can make your operating systems unbootable, if done improperly. You are responsible of what you do, please be cautious.

Bios-level boot menu

Modern BIOSes have an option for a "boot menu". Look at the BIOS settings. It can even choose other boot options, like CD, USB or network boot. But it needs to press a key (often ESC, F10 or F12).

  • Pros: will work if you add or remove disks
  • Cons: no personalized labels, usually just brand name of disks

MBR-level boot menu

MBR is Master Boot Record, the first sectors of the hard disk the BIOS boot on.

You can install there an OS selector. It will occupy the first few sectors of the hard disk.

  • Pros: depend of particular program you choose. Independent of any OS installed, so you can install and remove OSes at will (even all of them), the menu will always work.
  • Cons: depend of particular program you choose.

There are various programs to choose. For years I've used extipl. It is minimalist (text-mode menu, no labels just partition numbers) but always worked for me whatever the changes on my disks.

It may not be obvious when you read a description of a bootloader if it is MBR-level or partition-level.

Partition-level boot menu

If you don't install a specific MBR, the default MBR installed by Windows will just give control to the first operating system found. You an customize there.

Windows XP and beyond are customizable using boot.ini. You can configure for a menu with personalized labels.

See this example from Dual booting XP on 2 hard drives - TechSpot Forums. Follow that link for explanation about risks.

[boot loader]
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="XP on primary drive" /fastdetect
multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="XP on backup drive" /fastdetect
C:\CMDCONS\BOOTSECT.DAT="Microsoft Windows Recovery Console" /cmdcons

There are probably some user-friendly tools to this more easily and prevent some dangers of manual editing.

  • Pros: friendly (though text+keyboard-based), configurable timeout.
  • Cons: attached to the OS, so if the OS is reinstalled or removed, the menu is lost.
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If both are XP

You can try and edit you boot.ini file.

To view and edit the Boot.ini file: Right-click My Computer, and then click Properties. -or- Click Start, click Run, type sysdm.cpl, and then click OK. On the Advanced tab, click Settings under Startup and Recovery. Under System Startup, click Edit.

Then, under opeating systems add yours

[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Windows XP Professional" /fastdetect
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS2="your other windows XP" /fastdetect
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