After receiving a blue screen with dire warnings I believe the message
was not sent to Microsoft because of a change that had to be made in
the web.config file of mozilla firefox.  Since my computer is
experiencing many problems,at this time, I would like to understand
what this message means and how to do what it suggests.The following
is a whole screen message I received.

Server Error in '/' Application.
Runtime Error
Description: An application error occurred on the server. The current
custom error settings for this application prevent the details of the
application error from being viewed remotely (for security reasons).
It could, however, be viewed by browsers running on the local server
machine.

Details: To enable the details of this specific error message to be
viewable on remote machines, please create a <customErrors> tag within
a "web.config" configuration file located in the root directory of the
current web application. This <customErrors> tag should then have its
"mode" attribute set to "Off".

<!-- Web.Config Configuration File -->

<configuration>
    <system.web>
        <customErrors mode="Off"/>
    </system.web>
</configuration>


Notes: The current error page you are seeing can be replaced by a
custom error page by modifying the "defaultRedirect" attribute of the
application's <customErrors> configuration tag to point to a custom
error page URL.

<!-- Web.Config Configuration File -->

<configuration>
    <system.web>
        <customErrors mode="RemoteOnly" defaultRedirect="mycustompage.htm"/>
    </system.web>
</configuration>

Hello ,

web.config file is a website configuration file. Typically when you
develop any JSP / ASP application you would have a server installed on
your machine. On the application directory you would have this
web.config file. It has nothing to do the different error messages you
might be receiving. The only thing I can think of is are you running a
.NET Development tool by anychance?

If this is not what you doing, do a simple task. Search for this file.
Open in notepad and set customErrors mode="Off" from "off" to "on" and
you would be able to see the complete details

regards,
Answerboy

Thank you AnswerBoyToronto! I do not know what a .Net Development tool
is. And I did as you requested--searched for web.config and it didn't
show up.  I was trying to copy a video file on my computer to a DVD
burner using Nero Vision which I had just upgraded with a download. 
So many things going on, I don't know where to look for the problem. 
I appreciate your help though.  Thank you. Cloverly