Getting mysterious 500 error on ColdFusion server after it worked fine for a while

 Try restarting the service for Coldfusion MX Application Server

 open services, location Coldfusion MX application server, shutdown and start up again.

500 nulls often are the result of the server running out of resources. Next time this happens check memory usage... on my dev system i get a 500 if jrun hits about 400mb usage. what you'll top out at depends on your system memory

usually (but not always) due a a bad query or some cf process running amuck due to bad coding

I tried restarting the service as well as the agents; still no go.  

 place a simple .html file in your web root and see if you can view that file through the browser (no coldfusion).   If not, we need to look at IIS instead of coldfusion.

 Verify where the IIS web site directory is pointing before doing this.

my system resources seem fine and there was no queries or anything running (to my knowledge) that would cause this problem.

do you have a dsn named either     service or  comp?

http://www.adobe.com/cfusion/knowledgebase/index.cfm?id=tn_18532

also may be a corrupt defaut-web.xml

http://devnulled.com/content/2006/07/how-to-quickly-fix-common-jrun-coldfusion-startup-problems/

that could be the error; does the CF installation put backup files anywhere (as obviously its too late to back it up since it may already be corrupt).

and no i dont have a dsn named either of those things (I looked that up prior to posting my question)

"does the CF installation put backup files anywhere"

no but you can try and copy and paste below...use notepad...word or wordpad with probably mess it up with weird characters

make sure there's no spaces or lines before the first line...

<?xml version="1.0" encoding="ISO-8859-1"?>

<!DOCTYPE web-app  PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">

<web-app>

 <display-name>Default Web Application Settings</display-name>
 <description>Settings </description>

<!--
 <filter>
   <filter-name>JRunTimingFilter</filter-name>
   <filter-class>jrun.servlet.filters.TimingFilter</filter-class>
 </filter>

 <filter-mapping>
   <filter-name>JRunTimingFilter</filter-name>
   <url-pattern>/*</url-pattern>
 </filter-mapping>
-->

 <servlet>
   <servlet-name>FileServlet</servlet-name>
   <servlet-class>jrun.servlet.file.FileServlet</servlet-class>
   <init-param>
     <param-name>browseDirs</param-name>
     <param-value>true</param-value>
   </init-param>  
 </servlet>

 <servlet>
   <servlet-name>ServletInvoker</servlet-name>
   <servlet-class>jrun.servlet.ServletInvoker</servlet-class>
 </servlet>

 <servlet>
   <servlet-name>JSPServlet</servlet-name>
   <servlet-class>jrun.jsp.JSPServlet</servlet-class>
   <load-on-startup>1</load-on-startup>
   <init-param>
     <param-name>keepGenerated</param-name>
     <param-value>false</param-value>
   </init-param>
   <init-param>
     <param-name>translationDisabled</param-name>
     <param-value>false</param-value>
   </init-param>  
   <init-param>
     <param-name>cacheTags</param-name>
     <param-value>true</param-value>
   </init-param>  
 </servlet>

 <servlet>
   <servlet-name>JSTServlet</servlet-name>
   <servlet-class>jrun.jsp.JSTServlet</servlet-class>
 </servlet>

 <servlet>
   <servlet-name>JspLicenseServlet</servlet-name>
   <servlet-class>coldfusion.license.JspLicenseServlet</servlet-class>
 </servlet>

 <servlet>
    <servlet-name>AxisServlet</servlet-name>
    <display-name>Apache-Axis Servlet</display-name>
    <servlet-class>org.apache.axis.transport.http.AxisServlet</servlet-class>
    <init-param>
      <param-name>use-servlet-security</param-name>
      <param-value>true</param-value>
    </init-param>
 </servlet>

 <servlet>
   <servlet-name>JRunStatistics</servlet-name>
   <jsp-file>/jrunx/instrument/Results.jsp</jsp-file>
 </servlet>

 <servlet-mapping>
   <servlet-name>FileServlet</servlet-name>
   <url-pattern>/</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
   <servlet-name>JspLicenseServlet</servlet-name>
   <url-pattern>*.jsp</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
   <servlet-name>JSTServlet</servlet-name>
   <url-pattern>*.jst</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
   <servlet-name>ServletInvoker</servlet-name>
   <url-pattern>/servlet/*</url-pattern>
 </servlet-mapping>

 <servlet-mapping>
   <servlet-name>JRunStatistics</servlet-name>
   <url-pattern>/JRunStatistics</url-pattern>
 </servlet-mapping>

 <welcome-file-list>
  <welcome-file>index.html</welcome-file>
  <welcome-file>index.jsp</welcome-file>
 </welcome-file-list>

 <!--
 <error-page>
    <exception-type>jrun.jsp.compiler.JSPCompiler$CompoundCompilerException</exception-type>
    <location>/jrun/jsp/error-pages/CompoundCompilerException.jsp</location>
 </error-page>

 <error-page>
    <exception-type>javax.servlet.ServletException</exception-type>
    <location>/jrun/servlet/error-pages/ServletException.jsp</location>
 </error-page>

 <error-page>
    <exception-type>jrun.jsp.parser.TokenMgrError</exception-type>
    <location>/jrun/servlet/error-pages/ServletException.jsp</location>
 </error-page>
-->
 <error-page>
    <exception-type>javax.io.FileNotFoundException</exception-type>
    <location>/jrun/servlet/error-pages/404.jsp</location>
 </error-page>

</web-app>

I tried that exactly as you said.  Still the same exact error

Yeah; I just uninstalled and reinstalled; bizarre.  Thanks.