machine.config <processModel> setting question

[Tim]

I'm having problems trying to do follow examples I've seen using the EventLog and Process classes. I'm getting security exceptions (access denied). I've seen in many articles/posts that setting the userName="SYSTEM" in the machine.config file's <processModel> element allows the aspnet_wp process to be able to do this. However, I still keep getting security exceptions. I'm working with IIS 5, ASP.NET v1.1.4322

Is there something besides setting the userName element to SYSTEM that I need do? In the IIS manager for the virutal directory, I've tried changing security settings (Integrated Windows authentication both on & off, anonymous access on and off) and I didn't see a change. Thanks.