Depending on what Microsoft programs you or your organization might be part of, there are a few ways to get the RTM version of Windows 8. If you have an MSDN Subscription or a TechNet Professional Subscription,
msdn account ekak nathuva download karanna bari nisa tama oya link tika damme....
Enterprise
http://msdn.microsoft.com/en-us/evalcenter/jj554510.aspx?wt.mc_id=MEC_132_1_4
(Sign in with your microsoft account. No MSDN, Technet subscription required machan)
Thanks machan 
