[HTTP Error 404.15]: when trying to login to CRM 2011

Hi,

When i try login in CRM 2011, irrespective of user, it shows me below error:

"HTTP ERROR 404.15"

THE REQUEST FILTERING MODULE IS NOT CONFIGURED TO DENY A REQUEST WHERE THE QUERY STRING IS TOO LONG.'

Server Detail

Winfdows server 2008 R2

SQl Server 2008

IIS 7.5

CRM 2011

Few points:

1. Have recently installed CRM, and was able to access it for few days.

2. Recently created few user & forms and till EOD was able to use CRM without error.

3. No changes were made to active directory user rights.

4. The next morning, error was shown.

I have checked it online and used various resolution method, but still no help.

Has any body faced this issue, kindly help!!!

Thanks in advance.