dotNetFramework 3.5 SP1 - get him from microsoft website because you need him to run any .NET program
Reflector - .NET Reflector enables you to easily view, navigate, and search through, the class hierarchies of .NET assemblies, even if you don't have the code for them. With it, you can decompile and analyze .NET assemblies in C#, Visual Basic, and IL. CodeSearch plugin for Reflector: - with this plugin you can search a string in Reflector Reflexil plugin for Reflector: - tools for modifying assemblies Xenocode Fox: - a good replacer for Reflector (NEW) ILDASM 3.5: - a decompiler for .NET programs which even shows opcode of instructions (this is the reason why is useful), Extract_hex_bytes - extract hexazecimal opcode, NEW: hex2il - convert opcodes to IL intructions, Msilma - MSIL analyser, ILASM - IL compiler