sir I need your help as an error message often occurred .It was 'LENOVO-PC error = LENOVO-PC: MPICH2 not installed or unable to query the host' I had closed the firewall according to the instruction.My version of MPICH2 was 'mpich2-1.4.1p1-win-x86-64' and my computer is operating on Win7-64 system. I really need a solution to the problem. Thank you very much. Your sincerely. ------------------ Lm Liu School of Energy and Power Engineering of Xi'an Jiaotong University No.28, Xianning West Road, Xi'an, Shaanxi, 710049,P.R.China