Malwares attempt to evade AV scanners using various obfuscation techniques. Packing is a popular obfuscation technique used by 80% of malwares. In this paper, we propose a generic unpacking mechanism to find the original entry point (OEP) using entropy analysis. The experiment using 110 packed executables demonstrates the proposed mechanism can locate the OEPs of 72% of the packed executables. Furthermore, we show how the mechanism could be applied to packed malwares.