So, you've decided to move your drive with Windows 2000 (or XP) to a new system, or upgraded your motherboard, and you now get the dreaded blue screen of death before the operating system gets to the desktop. All you get is a STOP 0x0000007B error (INACCESSIBLE_BOOT_DEVICE). What now???? Well, here's what you need to do...

Well, the first thing you need to do is to get the system working again, so, put the system back in the original working configuration. If you changed the motherboard, change it back to the original. If you moved the drive to a new system, place it in the old one.

Now, for people that understand what they are doing, and how to do it, here are the "quick" steps:
1 - Extract 'Atapi.sys,' 'Intelide.sys,' 'Pciide.sys,' and 'Pciidex.sys' from '%SystemRoot%\Driver Cache\i386\Driver.cab' (or SPx.CAB if it exists, where x is the latest service pack)
2 - Copy those four files to the following location: '%SystemRoot%\System32\Drivers' (do not replace files already there)
3 - Merge the registry file found below (copy the text to notepad and save as a .reg file), or better, download it here
4 - THAT'S IT! Move it to the new system (or change the motherboard), and your system should start up.

STEP BY STEP INSTRUCTIONS FOR THOSE THAT NEED IT:
1 - Click START, go to RUN, type in "CMD" (without quotes), hit ENTER
2 - At the command prompt, type in:
"CD %SystemRoot%\Driver Cache\i386" (without quotes) hit ENTER
"dir/w" (without quotes) hit ENTER
If you are running Windows 2000, check for SPx.CAB (where x is the highest number), in the following steps, use the SPx.CAB instead of DRIVER.CAB
(If you are asked to OVEBWRITE any file, choose NO)
"expand driver.cab -f:atapi.sys %SystemRoot%\System32\Drivers" (without quotes) hit ENTER
"expand driver.cab -f:intelide.sys %SystemRoot%\System32\Drivers" (without quotes) hit ENTER
"expand driver.cab -f:pciide.sys %SystemRoot%\System32\Drivers" (without quotes) hit ENTER
"expand driver.cab -f:pciidex.sys %SystemRoot%\System32\Drivers" (without quotes) hit ENTER
"exit" (without quotes) hit ENTER
3 - You should now be back at the Desktop, you need to download the registry file from HERE, save it to someplace you will remember, preferably your desktop. After it is downloaded, DOUBLE-CLICK on it, you will be asked if you wish to MERGE the contents with you registry, CHOOSE YES.
4 - THAT'S IT! Your system is prepared to be moved to another system/have the motherboard changed.

HERE IS THE REGISTRY FILE (COPY IT INTO NOTEPAD, AND SAVE IT AS A .REG FILE, OR BETTER, DOWNLOAD IT HERE)

********* START COPY AFTER THIS LINE *************
Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\primary_ide_channel]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="atapi"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\secondary_ide_channel]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="atapi"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\*pnp0600]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="atapi"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\*azt0502]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="atapi"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\gendisk]
"ClassGUID"="{4D36E967-E325-11CE-BFC1-08002BE10318}"
"Service"="disk"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#cc_0101]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_0e11&dev_ae33]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1039&dev_0601]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1039&dev_5513]
"ClassGUID"="{4D36E96A-E325-1!CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1042&dev_1000]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_105a&dev_4d33]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1095&dev_0640]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1095&dev_0646]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1097&dev_0038]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_10ad&dev_0001]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_10ad&dev_0150]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_10b9&dev_5215]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_10b9&dev_5219]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_10b9&dev_5229]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="pciide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_1106&dev_0571]
"Service"="pciide"
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_1222]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_1230]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_2411]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_2421]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_7010]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_7111]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\CriticalDeviceDatabase\pci#ven_8086&dev_7199]
"ClassGUID"="{4D36E96A-E325-11CE-BFC1-08002BE10318}"
"Service"="intelide"

;Add driver for Atapi (requires atapi.sys in drivers directory)

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\atapi]
"ErrorControl"=dword:00000001
"Group"="SCSI miniport"
"Start"=dword:00000000
"Tag"=dword:00000019
"Type"=dword:00000001
"DisplayName"="Standard IDE/ESDI Hard Disk Controller"
"ImagePath"=hex(2):53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,44,00,\
52,00,49,00,56,00,45,00,52,00,53,00,5c,00,61,00,74,00,61,00,70,00,69,00,2e,\
00,73,00,79,00,73,00,00,00

;Add driver for intelide (requires intelide.sys in drivers directory)

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\IntelIde]
"ErrorControl"=dword:00000001
"Group"="System Bus Extender"
"Start"=dword:00000000
"Tag"=dword:00000004
"Type"=dword:00000001
"ImagePath"=hex(2):53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,44,00,\
52,00,49,00,56,00,45,00,52,00,53,00,5c,00,69,00,6e,00,74,00,65,00,6c,00,69,\
00,64,00,65,00,2e,00,73,00,79,00,73,00,00,00


;Add driver for pciide (requires pciide.sys and pciidex.sys in drivers directory)

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\PCIIde]
"ErrorControl"=dword:00000001
"Group"="System Bus Extender"
"Start"=dword:00000000
"Tag"=dword:00000003
"Type"=dword:00000001
"ImagePath"=hex(2):53,00,79,00,73,00,74,00,65,00,6d,00,33,00,32,00,5c,00,44,00,\
52,00,49,00,56,00,45,00,52,00,53,00,5c,00,70,00,63,00,69,00,69,00,64,00,65,\
00,2e,00,73,00,79,00,73,00,00,00

************ END COPY ABOVE THIS LINE ***************