IDE Emulation Mode doesn't work

[zamarac]

I've a dual boot system: Windows 7 and XP. I can boot normally in WinXP in AHCI SATA mode and also IDE Emulation Mode. But in Windows 7 I can boot only in AHCI SATA mode, but when IDE Emulation is switched ON in BIOS of my ASUS P5Q mobo, the PC hangs at boot with 0x7B BSOD? It started happening after some Windows Update fixes were installed a while back - don't know exactly, since use IDE Mode only seldom, when connecting old IDE extra drive. Please suggest, how to troubleshoot and fix?

Edited January 6, 2012 by zamarac

[cdob]

Boot Windows 7 at AHCI mode. Run regedit. Set service pciide to start=0

[zamarac]

Thanks - it worked!

Initially I switched all IDE related services and drivers to Start=0 in ControlSet001 assuming PC will use it at boot, but it didn't. Then I followed with CurrentControlSet, and it did. Is my assumption correct that CurrentControlSet is remembered at reboot as ControlSet001 or as LastKnownGoodConfig? So next boot the OS uses ControlSet001 or LastKnownGoodConfig?

I ask because when OS is offline, there is no CurrentControlSet in its Registry, so its deleted at shut down?

Edited January 7, 2012 by zamarac

[cluberti]

CurrentControlSet is the current running boot, and it's saved to ControlSet00x when you shut down. When you boot, the last ControlSet00x that was used is used again, and the CurrentControlSet you see in the registry is actually just a symlink to the ControlSet00x that was booted from. After a successful boot sequence, another ControlSet00x is created (or overwritten) as a backup of the currently loaded ControlSet to be used as the Last Known Good control set to be used with the Last Known Good boot option. Microsoft talks about it in a KB article here.

[dencorso]

Run regedit and look ar HKLM\SYSTEM\Select

The value Default stores which ControlSet should become the CurrentControlSet, at the next boot.

More info here.

[zamarac]

Thanks a lot! But now I'm more confused.

Last time I checked, Select was set to 1. I fixed CS001 to pciide Start=0, and OS didn't boot. According to your posts, when OS was exited, CCS was saved at CS001, meaning pciide Start=3. But when it failed to boot in IDE mode, and I booted in SATA and looked again, CS001 was still with pciide Start=0, and CCS was with Start=3. How is that possible?

Edited January 7, 2012 by zamarac

[dencorso]

Multiple control sets (typically two) are kept, in the event that the settings contained in the currently-used one prohibit the system from booting. HKEY_LOCAL_MACHINE\System contains control sets labeled ControlSet001, ControlSet002, etc., as well as CurrentControlSet. During regular operation, Windows uses CurrentControlSet to read and write information. CurrentControlSet is a reference to one of the control sets stored in the registry. Windows picks the "real" control set being used based on the values set in the HKLM\SYSTEM\Select registry key:

* Default will be the boot loader's choice if nothing else overrides this

* If the value of the Failed key matches Default, then the boot loader displays an error message, indicating that the last boot failed, and gives the user the option to try booting anyway, or to use the "Last Known Good Configuration".

* If the user choose (or has chosen) Last Known Good Configuration, the control set indicated by the LastKnownGood key is used instead of Default.

When a control set is chosen, the Current key gets set accordingly.

From the Wikipedia link I gave and you didn't follow...