my website don't be run

hello

before i design a website and get free host from somme.com. then upload files.
all things was fine.
but now i update my website and upload myfiles.
but when type link of site in url of browser, i will face to this error:

Server Error in '/' Application.
Runtime Error
Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.

then i change "customErrors mode" in web.confog. but it is useless.
what should i do?

thanks

By "it is useless" do you mean it didn't provide a detailed description of the error or you don't understand the error it described?

For the time being, I'd upload a backup of your site so at least it is working again.

when i typed my web site address in url :
www.agrp.somee.com/default.aspx

the address will be change to:
http://www.agrp.somee.com/Error.aspx...=/default.aspx

but default.aspx are exist there.
i upload files sometimes. with and without publish.

but the error will be shown:
Server Error in '/' Application.
Runtime Error
Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.

when i typed my web site address in url :
www.agrp.somee.com/default.aspx

the address will be change to:
http://www.agrp.somee.com/Error.aspx...=/default.aspx

but default.aspx are exist there.
i upload files sometimes. with and without publish.

but the error will be shown:
Server Error in '/' Application.
Runtime Error
Description: An exception occurred while processing your request. Additionally, another exception occurred while executing the custom error page for the first exception. The request has been terminated.

It looks like you have an error in the default.aspx page then, if it runs locally when testing then there is probably something different in your local environment and the hosting environment that is causing this error.

What code is running on the page load? Are you relying on any other services such as a database or similar that isn't present or maybe not correctly configured at the host's end?