OllyDbg + 0llyICE – Most popular 32-bit & 64-bit disassembler and assembler

OllyDbg is a professional 32-bit assembler-level analyzing debugger from Germany, written for both Windows 32-bit and 64-bit, released and kept as freeware. As is known to all, it is really an edge tool for software cracking, and a must-have tool for many novices.