PEiD (short for PE iDentifier) is a well-known professional packer/cryptor/compiler detecting tool. It's so powerful that it can detect the types/signatures of almost any PE file packing tools (at present, the number has been more than 600 kinds). In addition to the official version, AppNee also provides you its full-plugin version, which can be treated as the most perfect one version (contains 60+ plugins and necessary runtime library files: mfc70.dll, msvcr70.dll, rtl70.bpl, vcl70.bpl) on the Internet at present. I do believe reverse engineers or software cracking/unpacking enthusiasts must like it very much.

Adobe Flash Player has already been critical for the day-to-day daily use of computer or even mobile phone. Alternative Flash Player Auto-Updater is a tiny app specially designed for keeping the version of your Adobe Flash Player on Windows up to date, which can automatically detect, download and install the latest version of Flash Player.

If you don't understand what is the hash value of a file, then, i don't think you have to study this application, because maybe you do not need to use it or even know it at all.