how to call windows service from c#.aspx page(plz help urgently needed)

You can use a WCF service hosted in the Windows Service.  
The ASP.NET performs as the client here and calls the methods of WCF service.
You can pass arguments to the method.

or

You can use MSMQ implementation.  The ASP.NET pushes a job to the queue and service will be listening to the queue and retrieves job.