windows 7 bootloop after CMOS reset

kenny0987 · Apr 20, 2016

Hi guys,
So mysteriously this morning, after putting the computer to sleep last night, it wouldn't start at all. So i held the power button till it turned off, but then when trying to restart it would bootloop before POST, it would get to the beep, then a few seconds later restart again showing nothing on screen.

I figured it might be my gpu (happened before, it's really old), so i removed and reseated it, and removed the CMOS battery too. Now it would boot upto the point of OS selection as i have windows 7 & Server 2012 installed, but now it won't boot any of them, freezes at their loading logos.

I've tried using startup repair, even bootrec commands. When i try making a backup of the BCD so i can rebuild it, it tells me the file doesn't exist, and i suspect this is due to the fact the assigned drive letters seem to have changed. Any ideas on how can i fix this?

Any help appreciated, thanks

techgeek · Apr 20, 2016

Not sure, but have you looked in the BIOS to see if the SATA mode is set to AHCI or IDE. If Windows was installed in IDE mode and when your reset the BIOS it defaulted to AHCI or even RAID, it will cause the boot to fail.

kenny0987 · Apr 20, 2016

I'm not sure what mode it was installed on. So i should try changing it in bios to a different mode or without that do more harm than good?

techgeek · Apr 20, 2016

No harm will come from changing it. I assume you weren't using RAID (you'd probably know if it was), so if it's set to IDE now, try AHCI, if it's AHCI, then try IDE.

I can't remember, but if you installed Windows under AHCI, you can successfully switch it to IDE and it will work. It's going the other way that causes the problem. Since Windows needs the AHCI driver installed and referenced in the registry so it can load it. So if it's using the IDE driver and the BIOS is set to AHCI, it will get to a certain point and fail because Windows is using the incorrect driver.

kenny0987 · Apr 20, 2016

Well there's good news and bad news. Good news is that now Server 2012 is bootable again

but windows 7 is still having issues. I'm thinking maybe i messed around too much with the original BCD, although now it gets further into the logo animation than before, not sure if that's relevant.

EDIT: To be more specific, when I use the original BCD, it shows up in the OS selection screen, but it hangs during the windows startup animation, and when i swap it out and rebuild the BCD, it won't even show up in the list of OS boot selection

techgeek · Apr 20, 2016

Does Window 7 and Windows Server 2012 reside on the same physical disk / different partitions? Or are they on separate disks?

kenny0987 · Apr 21, 2016

They are both on separate disks, with windows 7 as my main OS. Abit of an update, I completely removed the MBR and decided to redo it with each disk plugged in separately, which i prob should've done in the first place. Server 2012 boots up fine in both IDE or AHCI modes, but windows 7 still only gets to the startup animation. Wierd thing is when i try system repair, the report gives the message " Boot status indicates that the OS booted successfully". Could there be some other issue?

techgeek · Apr 21, 2016

Have you tried a Startup Repair for Windows 7?

kenny0987 · Apr 21, 2016

Yup, that's where i got the message in the report after it had done its thing, saying "Boot status indicates that the OS booted successfully", but it still won't boot

techgeek · Apr 21, 2016

How are you selecting which OS is booting? Is there a boot loader on the primary storage device? Or are you using boot selection after the computer POST's? Or is this still with one drive connected at a time?

kenny0987 · Apr 21, 2016

techgeek :

Prior to this issue, i would select the OS using boot selection after POST. But now trying to fix both at the same time was proving to be a headache, so I decided to fix em separately then update the boot record with both installations once I had them both up and running. At the moment I've rebuilt the BCD on the Server 2012 drive, and it boots fine regardless whether I select IDE or AHCI in the bios.
The windows 7 drive is the issue now, coz startup repair tells me everything is ok even after running at least 3 times, but when i run bootrec /scanos, it tells me it does not detect any windows installations

techgeek · Apr 21, 2016

If you boot to Windows Server 2012 with the Windows 7 drive connected, can you browse the Windows 7 drive? Are all the files there?

kenny0987 · Apr 21, 2016

Yep I can see all the files there, no errors reported by the drive

techgeek · Apr 21, 2016

kenny0987 :

techgeek :

Prior to this issue, i would select the OS using boot selection after POST. But now trying to fix both at the same time was proving to be a headache, so I decided to fix em separately then update the boot record with both installations once I had them both up and running. At the moment I've rebuilt the BCD on the Server 2012 drive, and it boots fine regardless whether I select IDE or AHCI in the bios.
The windows 7 drive is the issue now, coz startup repair tells me everything is ok even after running at least 3 times, but when i run bootrec /scanos, it tells me it does not detect any windows installations

So when you did:

bootrec /scanos

You were booting from the Windows 7 install DVD and you'd selected Repair you Computer > System Recovery Options > Command Prompt?

kenny0987 · Apr 21, 2016

techgeek :

Yup, I made a bootable repair usb since my windows was a digital copy. I used command prompt to rename the existing bcd and rebuild it using /rebuildbcd, at which point it detects it, but when i reboot, startup stalls at the windows logo and reboots, and getting back into the command prompt, it no longer detects the installation, though startup repair will sometimes report an issue on the first run, here's the report:

Code:

Problem Event Name:         StartupRepairOffline
Problem Signature 01:        0.0.0.0
Problem Signature 02:        6.1.7600.16385
Problem Signature 03:        unknown
Problem Signature 04:        21199474
Problem Signature 05:        SystemDisk
Problem Signature 06:        43
Problem Signature 07:        NoRootCause
OS Version:                  6.1.7600.2.0.0.256.1
Locale ID:                   1033

techgeek · Apr 21, 2016

Have you tried the vanilla System Repair?

kenny0987 · Apr 21, 2016

techgeek :

Which one is that?
An idea i was thinking about was to use EasyBCD on server 2012 to edit the boot menu and add in windows 7 manually, would this work?

techgeek · Apr 21, 2016

It might assuming there isn't anything wrong with the Window 7 install, and your Windows Server 2012 was the default boot drive.

kenny0987 · Apr 21, 2016

Im not sure how to check if there is anything wrong with the windows 7 install, but Server 2012 was not the default boot drive before the problem came up. It is now since there is no other OS to boot, but that seems to be easily changeable through Msconfig if im not mistaken.

techgeek · Apr 21, 2016

Well EasyBCD is pretty straight forward. It will either find the Windows 7 install or it won't. It can't hurt anything.

kenny99 · Apr 21, 2016

techgeek :

So i tried that method, it found the boot files and created the boot menu entry, but the problem still persists.

Im thinking that this may be a different problem, when i tried booting in safe mode it hangs at Aswrvrt.sys, which seems related to be an Avast file which I have installed on the windows 7 drive. I then ran chkdsk with the flags /f and /r and left it running overnight, just checked the logs this morning and windows reports everything is ok.

Any ideas with this?

techgeek · Apr 22, 2016

At this point I'm not sure what to say. When you are in the command prompt for Repair, have you tried to run:

sfc /scannow

I'm not 100% sure it'll run from there, but I think it should.

windows 7 bootloop after CMOS reset

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