Server Unavaillable

Hi, when i typehttp://localhost/helloWorld.aspx. . I get this error.
____________________________________________________________________________________________________

Server Application Unavailable

The web application you are attempting to access on this web server is currently unavailable. Please hit the "Refresh" button in your web browser to retry your request.

Administrator Note:An error message detailing the cause of this specific request failure can be found in the application event log of the web server. Please review this log entry to discover what caused this error to occur
-----------------------------------
It is not only this asp.net page but all my previous web applications also give the same error.
Another thing , When i try to create asp.net application, i get this error.
--------------------------
The Web server reported the following error when attempting to create or open the Web project located at the followingURL:'http://localhost/WebApplication1.' 'HTTP/1.1 500 Internal Server Error'.
-----------------------------------
A point to note was that I was formerly able to run these applications when I was at home and now I have shifted to a hostel which is on campus network.Wonder if the problem is due to this??
Need help ... Thanks in advance.

Well...did you look at the Application Log of the Event Viewer, like the instructions tell you? See where it says "Administrator Note".
What did the Log say?

Are you hosting this application on your local PC or Hostel PC.
Also since you are connected from your hostel It can be that some sort of firewall is blocking you.
Disconnect from the Hostel Network and try to view the pages.

Yah , man it is my PC..
Anyway, I did check my Event Viewer.And found there were 2 errors.
This was the first
Event Type: Error
Event Source: ASP.NET 1.1.4322.0
Event Category: None
Event ID: 1007
Date: 9/7/2005
Time: 12:28:22 PM
User: N/A
Computer: ENDOFDAYS
Description:
aspnet_wp.exe could not be launched because the username and/or password supplied in the processModel section of the config file are invalid.

For more information, see Help and Support Center athttp://go.microsoft.com/fwlink/events.asp.

And this the second.

Event Type: Error
Event Source: ASP.NET 1.1.4322.0
Event Category: None
Event ID: 1084
Date: 9/7/2005
Time: 12:28:23 PM
User: N/A
Computer: ENDOFDAYS
Description:
aspnet_wp.exe could not be started. The error code for the failure is 80004005. This error can be caused when the worker process account has insufficient rights to read the .NET Framework files. Please ensure that the .NET Framework is correctly installed and that the ACLs on the installation directory allow access to the configured account.

For more information, see Help and Support Center athttp://go.microsoft.com/fwlink/events.asp.
Anyone knoes wat is causing this errors.
Thanks for all helps..

That would explain your errors for sure.
I haven't seen these messages before, but it sure looks like something is messed up with your permissions and/or .NET install. Did you install IIS after .NET maybe? I wonder if this is a job foraspnet_regiis.exe -i ?
If this were me, I'd consider just re-installing the .NET framework and ensure I was logged in with Adminstrator rights when I did so.
Hope that helps.