Even though arguably my main role with my work is IT support (most of my time is spent with web development), it's not too often that I get to stretch my desktop problem solving skills.  So today was a bit of a treat as I got to learn a few tricks.

A staff PC would not boot into Windows, instead it would instantly reboot after the Windows splash animation.  So first thing was to boot in safe mode.  This didn't work either but I was able to identify the the boot process failed when attempting to load BTHidMgr.sys.  A quick search on Google and you'll find this isn't a rare problem, but it has very rare solutions.  I did, however, learn that this file relates to Blue Tooth drivers, in this case, most likely loaded with some mobile phone connectivity software.

All of the solutions I found on Google suggested running chkdsk from the recover console, or re-installing Windows XP in repair mode.   I had my doubts that chkdsk would fix a corrupt driver, and in our organsition our operating system is managed centrally, so repairing by re-installation of XP from a CD didn't seem like a good idea.

So, I needed to find how to stop a driver from loading.  It wasn't difficult to find mention of the listsvc and disable commands that can be ran from the Windows recovery console.  Listsvc lists all drivers and services that are loaded, and disable allows you to disable any of them.

My problem now was that I couldn't log into the recovery console.  It didn't prompt for which system to log into, it didn't ask for a password, and I the logon command did nothing.  There was no feedback as to suggest what the problem might be.

More searching and I found reference to a situation where someone else was unable to log into the recovery console whilst trying to fix another issue.  They were getting invalid password messages, but I read on to learn about a very handy boot disk called Offline NT Password & Registry Editor, Bootdisk / CD - a tool not many administrators would want their users to know about.  You can boot off the disk and use it to set the administrator password to null, or make modifications to the windows registry, and most importantly, change the registry settings for the recover console.

I assumed the above mentioned boot disk was going to disable the password requirement, but after I let it do its thing, rebooted and started up the Windows Recover console it prompted me immediately for the admistrator password.  Success.  I guess the recovery console was disabled all together.

I then ran listsvc to identify the Blue Tooth driver, BTHidMgr, and disabled it using disable.  I rebooted and the PC ran a disk check and we were on our way.  Far easier than backing up all the users data, re-installing windows and all his software - which would have been the recommendation had I spoken to the department responsible for managing the operating system.