Hi, you find the required information in the MSDN online:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winprog/winprog/windows_api_reference.asp
and more specific the "SendInput" at:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/winui/winui/windowsuserinterface/userinput/keyboardinput/keyboardinputreference/keyboardinputfunctions/sendinput.asp
Regards,
Mattias Ericsson
Endevo (www.endevo.se)
Gothenburg, Sweden