About OllyDbg and Instalation

OllyDbg is an x86 debugger that emphasizes binary code analysis, which is useful when source code is not available. It traces registers, recognizes procedures, API calls, switches, tables, constants and strings, as well as locates routines from object files and libraries. Version 1.10 is the final 1.x release. Version 2.0 has recently been released, and OllyDbg has been rewritten from the ground up in this release. The software is free of cost, but the shareware license requires users to register with the author. The current version of OllyDbg cannot always disassemble binaries compiled for 64-bit processors, though a 64-bit version of the debugger has been promised.


OllyDbg is often used for reverse engineering of programs. It is often used by crackers to crack software made by other developers. For cracking and reverse engineering, it is often the primary tool because of its ease of use and availability.[4] It is also useful for programmers to ensure that their program is running as intended.

• Intuitive user interface, no cryptical commands
• Code analysis - traces registers, recognizes procedures, loops, API calls, switches, tables, constants and strings

• Directly loads and debugs DLLs
• Object file scanning - locates routines from object files and libraries
• Allows for user-defined labels, comments and function descriptions
• Understands debugging information in Borland® format
• Saves patches between sessions, writes them back to executable file and updates fixups
• Open architecture - many third-party plugins are available
• No installation - no trash in registry or system directories

• Debugs multithread applications
• Attaches to running programs
• Configurable disassembler, supports both MASM and IDEAL formats
• MMX, 3DNow! and SSE data types and instructions, including Athlon extensions
• Full UNICODE support
• Dynamically recognizes ASCII and UNICODE strings - also in Delphi format!
• Recognizes complex code constructs, like call to jump to procedure
• Decodes calls to more than 1900 standard API and 400 C functions
• Gives context-sensitive help on API functions from external help file
• Sets conditional, logging, memory and hardware breakpoints
• Traces program execution, logs arguments of known functions
• Shows fixups
• Dynamically traces stack frames
• Searches for imprecise commands and masked binary sequences
• Searches whole allocated memory
• Finds references to constant or address range
• Examines and modifies memory, sets breakpoints and pauses program on-the-fly
• Assembles commands into the shortest binary form
• Starts from the floppy disk 
• and many more....

Instalation/running Ollydbg

first download the application
then locate and click OllyDbg.exe