Solved Registry is corrupt after uninstalling Avast

[Cliff S]

Have you tried repairing your boot loader? If you're using UEFI(which I would guess):
source

to recover the loader (BCD) configuration, you have to boot from the original installation Windows 8 DVD (or a recovery disk or a special EFI bootable flash drive) and open the command line choosingSystem Restore – > Troubleshoot-> Command Prompt or pressing Shift+F10).

Start diskpart:

1

diskpart

Display the list of disks in the system:

1

list disk

Select the disk with Windows 8 installed (if there is one disk in the system, it will have zero index):

1	sel disk 0

Display the list of volumes in the system:

1

list vol

In this example, you can see that the EFI volume (it can easily be recognized by its size of 100 MB and FAT32 file system) has the index volume 1, and the boot volume with Windows 8 installed is volume 3.
Assign any disk letter to the EFI volume:

1	select volume 1

1	assign letter K:

Close diskpart:

1

exit

Go to the bootloader directory in the hidden volume

1	cd /d k:\efi\microsoft\boot\

Recreate the boot sector on the boot partition

1	bootrec /fixboot

Delete the current BCD configuration file by renaming it (save the older configuration as a backup):

1	ren BCD BCD.bak

With bcdboot.exe, create BCD store again by copying the boot files from the system directory:

1	bcdboot C:\Windows /l en-us /s k: /f ALL

where C:\Windows – is the path to the directory with Windows 8 installed.
/f ALL – means that the boot files have to be copied including those for UEFI and BIOS computers (potential ability to boot in EFI and BIOS systems)
/l en-us – is a type of the system locale. By default, en-us – English (USA) is used.
Now you have to restart your computer. Then in the list of bootable devices there appears Windows Boot Manager where you can choose desired operating system to start.

 

[Jafaremraf]

Thanks Cliff S. I've made some tentative progress following your guide, but before I go any further I just want some reassurance that I won't make anything worse! This is new ground for me and it is very daunting! If this does work - great! But if it doesn't , how easy will it be to go back to where I am now?

 

[Cliff S]

Thanks Cliff S. I've made some tentative progress following your guide, but before I go any further I just want some reassurance that I won't make anything worse! This is new ground for me and it is very daunting! If this does work - great! But if it doesn't , how easy will it be to go back to where I am now?

Could you please wait. I Private messageda more advanced user to answer your question, I have personally never used BCD for UEFI (just MBR rebuild in Windows 7.

 

[Kari]

... but before I go any further I just want some reassurance that I won't make anything worse!

Any more reassurance is certainly difficult to give. As always with computers, the best we can tell you is to say it should work without issues. From https://technet.microsoft.com/en-us/library/ee221031(v=ws.10).aspx:

Support for both BIOS and UEFI firmware

UEFI is the next generation of firmware architecture that is designed to replace the BIOS architecture. The new Windows boot environment is designed for both BIOS and UEFI and uses a common data store that can exchange boot configuration information between the firmware, the boot loader, and boot applications.

This support article is also a good reference: https://technet.microsoft.com/en-us/library/dn336950.aspx?f=255&MSPPError=-2147217396

Kari

 

[Cliff S]

Thanks Kari

 

[Jafaremraf]

That's okay, I understand. If I want to try and resolve it myself then I have to take risks...... It's only because it's new to me that I'm being a wuss - and the fact that it's my 12 year old's precious gaming PC = loads of pressure!

 

[dencal]

Hi Jane.
Try this simple suggestion
In Admin Command Prompt type the following
diskpart then select your disk then type recover.
Good Luck.

 

[Cliff S]

That's okay, I understand. If I want to try and resolve it myself then I have to take risks...... It's only because it's new to me that I'm being a wuss - and the fact that it's my 12 year old's precious gaming PC = loads of pressure!

OW! A 12 year olds...just starting the teen years, that can be brutal. Just read a litte more on the subject BCD and you should be good. It is a lot easier a/less complicated with the old MBR but UEFI has a ton of benefits.

 

[Jafaremraf]

Hi Jane.
Try this simple suggestion
In Admin Command Prompt type the following
diskpart then select your disk then type recover.
Good Luck.

i don't know what this does, but it said The RECOVER command completed successfully. PC still doesn't work though! Think I'll have to try repairing the boot loader...... (Takes deep breath....)

 

[KYHI]

please get back into command prompt (either via recovery or setup media)

Type> diskpart
type> list disk
type> list volume

post a pic..

 

[dencal]

Hi Jane
Try this to obtain the bootloader, again using the Admin command prompt
bcd C:\Windows
Note there is a space between bcd and C
Also I assume you are using C drive, if another change C to whatever it is
Then restart computer.

 

[KYHI]

also it is

C:\windows\system32\sfc.exe /scannow

and it is

Dism /Image:C:\ /Cleanup-Image /RestoreHealth

and it is

C:\Windows\System32\bcdboot C:\Windows

 

[Jafaremraf]

please get back into command prompt (either via recovery or setup media)

Type> diskpart
type> list disk
type> list volume

post a pic..

Hi Kyhi

here is the pic

 

[KYHI]

OK, UEFI and GPT

You have gotten a lot of advice - but you are in X
the commands need to be run using C

As I have listed above

 

[Jafaremraf]

Sorry I don't know why that pic has turned upside down

 

[Jafaremraf]

Ok..... So I changed to C and entered each of those commands. This pic shows the outcome of all of them. Does this reveal anything?

 

[KYHI]

yeah there is a repair pending..

try this

dism /image:C:\ /cleanup-image /revertpendingactions

then try booting into safemode or using the commands above again

 

[Jafaremraf]

yeah there is a repair pending..

I know...... But I'm in a loop - I restart like it suggests and I'm still on the blue screen.

 

[dencal]

Jane
Do try post 31
Some commands are not possible in Windows PE
Have posted your att the right way up

 

[KYHI]

try this

dism /image:C:\ /cleanup-image /revertpendingactions

then try booting into safemode or using the commands above again