I added another hard drive to my PC and I was hoping that I could boot from either drive by changing the BIOS whenever I wanted to switch. I installed XP on the new drive with the other disconnected and then I reconnected it. When XP saw the old drive I think it branded it by writing in its boot sector. Now when I change the BIOS to boot from the old drive it will still boot from the new and it will always keep the drive letters the same. Thats not what I wanted. I wanted the boot drive to always be C and the other drive to be D. In case of a hard drive failure I want to be able to switch to the other drive and keep right on trucking. Is there anyway to turn off this obnoxious behavior displayed by XP?

The system RESTORE feature 'monitors' both Hard Drives by default. Go to System Restore Settings and you can turn of the monitoring of the D Drive. Windows XP labels the HDD but BIOS doesn't get affected by this. If you want IDE1 or IDE2 to be the first bootup then HDD1 or HDD2 will be selected.

Not sure what Brian is going on about with System restore. That has nothing to do with the boot sector or drive leetering. Starting up an installed OS will not affect the boot sector of another drive, nor the boot files. Computers are really "stupid" during the boot process. What IDE was the XP drive hooked up to when you installed XP? This will make a difference in the boot.ini file on THAT drive - rdisk(x) vs rdisk(0). What changes did you make to the original drives boot files and boot.ini? One of my systems has a multi boot disk as the 1st Primary IDE master drive (NT4 on the C:). I removed the drive and put in another drive in its place (1st Primary IDE master). Installed XP to it. Removed that new XP drive and put the original multi boot drive back in. Put the XP drive on another IDE channel (1st Primary IDE slave). Copied the XP boot files, NTLDR and NTDETECT.COM to the original drive (they are not backward compatible). Changed the boot.ini file to reflect the IDE channel (rdisk(1) in this instance) and the XP boot folder. Added: multi(0)disk(0)rdisk(1)partition(1)\WINDOWS="Windows XP Pro" /fastdetect Because I installed XP on the only drive, 1st ACTIVE partition, no matter where I place it in the IDE string, it will ALWAYS boot up as the C: drive. I can BIOS change the particular IDE boot device, but it will still come up C:. The multi boot drive's C: is NT4. This drive comes up as D: under XP. But when NT4 is booted, the NT4 partition is C:. XP came up as G: because the other partitions were in existence (and lettered) before the new XP drive (ie I already had a D: drive assigned under NT4). I changed the drive lettering (in NT4's Disk Admin) to make the XP drive D:. Keep in mind that you wont be able to change the drive letter for a "system drive" (the drive you boot from).

Michael, I installed the new drive as a master on the end of the primary IDE cable. I moved the old drive that was in that position to the middle connector of that cable and switched it to a slave but I left it disconnected temporarily. I booted off the XP CD and did a clean install on the new drive and then I shut the PC down and reconnected the old drive. After I restarted and changed the BIOS to boot from the old drive though it looks like it is still booting from the new drive because the windir variable is set to d:\windows while it is set to c:\window when I boot from the new drive. I haven't edited any boot.ini files. I am trying to get each drive to boot to its own copy of XP but the boot sector of the old drive must have an instruction to boot from the new drive. Thanks for your help.

Where is that "windir variable is set to d:\windows" that you're looking at? The only "instruction" for which OS to boot is in the boot.ini file. It is done via the ARC path. IDE0 master HDD is rdisk0, IDE0 slave is rdisk1, IDE1 master is rdisk2 IDE1 slave is rdisk3. The boot sector itself will not cross over to another physical HDD in order to boot. You haven't edited the boot.ini file on the original drive. This still points to rdisk(0), part(1) to boot. The new XP drive is that rdisk(0). You would need to edit that drive's boot.ini to reflect that it is the 2nd drive now - rdisk(1). Telling the BIOS which disk to boot does not change the ARC path. There's one of the things I don't understand. Why bother with changing the BIOS when you can do the same thing via setting up the boot.ini file on the bootable drive? The drives will both be visible in Explorer, so its not like you are protecting anything by BIOS booting either drive.

You can see the windir variable by typing "set" in the command window after executing "cmd" in the run window. It shows where the copy of windows is that you are executing. I think I am beginning to see the light about booting though. I was only using the BIOS because I didn't know you could do the same thing with boot.ini; I am trying to create a hot backup. One that I can alternate using so I can be sure its working just like the other. I intend to use "QuickSync 3" by Iomega to keep my applications and data synchronized between the drives. Now I've got another problem that I created while trying to set all this up. I changed the drive letter assignments on the old drive using computer management. Since the old drive was booting from the new and showing that drive as C and I wanted the old drive as C; I changed C to F, then D to C, and then F to D. E is the CD-Rom. The problem is I can't change it back. When I try to change C to F I get an error message saying "This volume contains a pagefile." Can I delete the pagefile so that I can change the drive lettering back the way it was? Thanks for your help.

The problems of trying to trouble shoot when you're not there to see what went on! Oh my! I did your set command. My setup still shows C:\. I have another system that I diddled with. It too shows C:\ for the SET, when I know it has booted from the 2nd drive (see NT post 18519 if you want). At what point did you SET, before or after the Disk Manager change? Regarding the pagefile. Be careful. You can set your install to an infinite boot loop by screwing with the page file in the wrong manner. Try setting your pagefile to the other drive. Reboot when it askes you to. If everything works the same, then make a boot disk. Format a floppy in XP (any one will do), copy NTLDR, NTDETECT.COM and the BOO.INI files to it. This should boot you to the GUI logon screen. TEST IT to make sure it works. Try switching your drives around (via Disk Manager), back to what they were. At worst, you may have to go back to having only the original drive installed and starting from scratch.