Problem in licence key activation

sir,

     i avinash samal metronet. while tried active server 2008 r2 standard giving product key saying product key not valid. valid product key. server important us. please me possible.

regrades 

avinash samal

mobile no- +91 9620841275

metronet

try running, windows volume license activation diagnostics tool

download : http://support2.microsoft.com/kb/2671818

Windows Server  >  Server Manager