I have a similar problem (I think)... Turning the service off may stop the crashing, but it might prevent other dell system software from running properly.
In my event logs under the windows system logs I notice that DellMgmtAgent is getting errors every time I reboot. The service does eventually start, but if I try to log into windows before that service finally starts I crash the computer.
I believe this service is related to my FIPS fingerprint reader pad on my keyboard and/or its related Dell security software.
Do you have any Dell security hardware running on your computer? I am running a Precision Mobile Workstation M6800, but I believe the security hardware on this computer is similar to the Precision Desktop Workstations.
If you turn this back on in your system and reboot but dont log into windows for a few minutes, does the computer crash? I believe the problem is related to a delay in the service loading. If you try to use the computer before the service loads, then it crashes. If I wait a minute or 2 before logging in, then everything is fine. I suspect logging into windows before the service starts and the resulting startup of the rest of the dell security framework causes the crash if that service isnt yet running.
Maybe the solution is to delay the rest of the dell secutiry framework from starting so the Dell Management Agent service has time to load first.