Need to edit registry on non-booting Windows 7 installation

[mysterons]

Hi,

I've got a problem with my Windows 7 installation in that - it wont boot! Either in normal or safe mode!

I've tracked the problem down to a driver - CTMMount.sys which was installed by a recent installation of Comodo Time Machine - which has since been uninstalled but doesnt look like the uninstallation has worked correctly.

Therefore I could do with editing the registry/startup procedure so that this file doesnt attempt to load and then I can get back into Windows 7 - has anyone any idea how I can do this?

Thanks

Ewan

 

[electrotune1200]

Why don't you just try a startup repair? It's probably a bit safer.
http://www.sevenforums.com/tutorials/681-startup-repair.html?filter[2]=Performance Maintenance

 

[Tews]

If you cant boot into Windows, how are you going to edit the registry???? If you can, open msconfig/startup and disable it from there...

 

[mysterons]

Why don't you just try a startup repair? It's probably a bit safer.
http://www.sevenforums.com/tutorials/681-startup-repair.html?filter[2]=Performance Maintenance

The startup repair tool says that it cant fix the problem as its due to a "recent software change" unfortunately.

 

[mysterons]

If you cant boot into Windows, how are you going to edit the registry???? If you can, open msconfig/startup and disable it from there...

Thats exactly the problem, I'm wondering if or how I can do this ? I dont really want to reinstall windows as obviously theres a lot of work involved in getting the machine (that I use for work) up and running again.

On a side note - if I do have to reinstall windows - will doing so empty the contents of the existing User folders?

 

[electrotune1200]

You can re-install Windows... Just don't format the drive.

You can pull all of your important data from the Windows.old folder.

 

[mickey megabyte]

Tews, this isn't as daft as it sounds,

i've got somewhere a version of bartpe (hawkpe) which is a sort of windows xp bootable livecd. it's got a copy of 'remote regedit' on it that you could use to fix a broken xp registry with.

however, i really don't know if a windows 7 version is possible, you'll need to spend some time googling.

 

[Aphelion]

If you can access the drive from another OS why not just go in, find all instances of CTMMount.sys and delete them, that is, if loading the driver is what's crashing the system. It should boot if the file is unavailable.

I have BartPE, it's based on XP, saved my butt a couple of times.

Ap

 

[Barman58]

If you have the Win7 Install disk you may be able to adapt the instructions here to access the registry

http://www.sevenforums.com/tutorials/56864-user-account-password-change-winre.html

Use the command prompt to access regedit - may work depending on the state of the actual reg files

 

[Bill2]

You can edit the registry offline i.e. from outside windows, using a PE environment. Boot from the win7 install dvd or a Bart PE, then navigate to the Command Prompt. If using the install dvd, you would need to reach there via the system recovery menu.

At the command prompt, type regedit.exe, hit Enter.

Now, the important part. Since you are in PE, you cant access registry keys as if you were in windows. You would need to use the "Load Hive" command at start, do whatever you want to do, then use the "Unload Hive" command.

See this page.

How to edit the registry offline using BartPE boot CD ?

There would be many other pages, just google for "offline edit registry" or something similar.

 

[Barman58]

As an alternative there is the old shool method

You may have to physically move the HDD to another working system If you do not have a dual boot option on the original system or access to a live CD for the copying stages

• Boot the other computer with a boot diskette or dual-boot OS and then copy the problem hive file to a removable media or directly across the network to your system.
  
• Log in as administrator on your system and run REGEDIT.EXE.
  
• In the Registry Editor, select either the HKEY_LOCAL_MACHINE or HKEY_USERS window, and then choose Registry | Load Hive.
  
• Locate the file copied to the system in step 1, select the file, and click Open. This loads the hive into the local registry as a subkey of the selected key.
• Make the necessary changes to the damaged hive and then choose Registry | Unload Hive.
• Copy the hive file back to its original location on the problem computer. Restart to test the system.

 

[mysterons]

Thanks for all the replies so far. Heres an update of where I am :

The machine has 2 hard disks - disk 1 (80Gb solid state) which has 2 partitions - 100Mb system reserved and the remaining partition with the original Win 7 installation on it. Disk 2 is a 1.5Tb Serial ATA.

I've installed Windows 7 to the second disk, after doing so disk 1 does not get drive letters assigned. Gone into drive management and I can assign a drive letter to the 100Mb partition but not the larger Win 7 partition.

If I put the Windows 7 DVD in - and ask it to install to the partition on disk 1 originally containing Windows 7 - it says it cannot install to this drive as its an unknown partition type.

Loading the original Windows 7 installation does the same as before - ie in safe mode it will load a pile of drivers and then hang at the message of "Loading \Windows\SysWow64\CTMMount.sys".

The problem originally occurred after installing Comodo Time Machine.

I'm at the stage now where I just need access to this original drive so that I can copy the contents of the Users folder somewhere else - at this point I will be happy to delete and recreate the partition and reinstall Windows 7.

Anyone got any further ideas/suggestions?

Thanks

Ewan

 

[Jacee]

This 'service' :sarc: is located here:

c:\windows\system32\drivers\CTMMOUNT.sys

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Run]
COMODO Internet Security"="c:\program files\COMODO\COMODO Internet Security\cfp.exe


I have read that there is an "uninstall" in CTMMOUNT.sys

 

[mysterons]

Issue resolved

Problem solved!

I ran testdisk - used this to firstly copy the files off the partition that windows couldnt access and then used it to re-write the MBR for that disk.

Disk then appeared correctly in the second windows installation.

Removed ctmmount.sys - rebooted the original windows installation - all works fine!

Thanks for all your help!

 

[Jacee]

Thanks for reporting back!