System Event Notification Service doesn't start - can't escalate to Admin

Question

I'll list my symptoms...

1. Running Windows 7 RTM 32-bit.
2. I can't log in as a non-admin user, failure to connect to the System Event Notification Service
3. If I log in as an admin user, I can't run anything as administrator (error: The system could not find the environment option that was entered), so I can't get into the Event Viewer, or run setup.exe off the Win7 disk, list the services, etc.
4. If I run "sfc /scannow" everything reports normal.
5. If I boot to "Repair my computer", the System Repair reports everything normal.
6. If I boot to "Repair my computer", and go to the Command Prompt, "netsh winsock reset" reports "The system cannot find the file specified"
7. If I boot to "Repair my computer", and go to the Command Prompt, I can't run setup.exe off the Win7 disk, because I'm in Safe Mode.
8. I'm running out of ideas, short of installing the OS again. I'd prefer to Upgrade/Fix the installation I have, rather than installing a clean copy, but I can't do that without fixing point 3.

All the web pages I can find about this error describe solutions that involve running processes as administrator, but I can't do that (see point 3 above).

Answer 1

I've made some progress in this.

In Safe Mode's command prompt, I've disabled UAC.

reg.exe ADD HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System /v EnableLUA /t REG_DWORD /d 0 /f

Now I can run setup.exe off the Win7 setup disk as admin, and should be able to repair (by doing an "upgrade") my installation.

Having disabled UAC, I still couldn't get into the Computer Management window, it failed with an "Unspecified Error". I managed to run mmc.exe and attach compmgmt.msc, but I still couldn't into the Event Viewer, because the service wasn't running (and wouldn't start when I tried).

So now I'm going to do an "upgrade" and see how that goes.