Cannot Start IIS on my PC: COM+ System Application: Access is Denied

I'm trying to do some web development. I cannot start IIS (I need to run some Web Services).

As of about a month ago, the "COM+ System Application" service has started failing with this error:

The COM+ System Application service failed to start due to the following error: Access is denied.

DCOM also logs an error in the event log:

DCOM got error "Access is denied. " attempting to start the service COMSysApp with arguments "" in order to run the server: {ECABAFBC-7F19-11D2-978E-0000F8757E2A}

When I start IIS and the WWW service, everthing seems to work until I hit port 80 on my machine at which time the IIS/WWW services both crash unexpectedly:

The World Wide Web Publishing service terminated unexpectedly. It has done this 1 time(s).

The following event is placed in the application log as well:

The run-time environment has detected an inconsistency in its internal state. This indicates a potential instability in the process that could be caused by the custom components running in the COM+ application, the components they make use of, or other factors. Error in f:\xpsp3\com\com1x\src\comsvcs\package\cpackage.cpp(1184), hr = 80070005: InitEventCollector failed

I have searched google until my fingers are numb. I've searched this site to no avail as well.

I have tried:

running the COM+ System Application service as an administrator.
reinstalling SP3 for XP
giving the "SERVICE" account full control to %SYSTEMROOT%\Registration
removing XP Security hotfixes installed about the time it stopped working
I've removed and reinstalled COM+ (it's possible, check google)

Any insight on the COM+ subsystem, it's files and settings or just how it operates would be greatly appreciated.

I need to get this problem resolved so I can get back to work.

Solution

Sorry all.

I forgot to update this when I found the solution... Well, it was self-inflicted. Some months ago, I removed the execute permissions from dllhost.exe. I hadn't been coding asp.net web apps at the time so I didn't notice the problem and couldn't put two and two together very quickly.

I eventually found it by turning on file system failed auditing on my Windows folder hive. I saw a mess of access denied messages related to dllhost.exe and remembered what I'd done.

Thanks for the help.