RawTherapee is a free open source application for opening and editing RAW image files. It works on all major operating systems such as Windows, Linux and Mac OS X.
You got a .rar file and you don't how to open it, some one asked you to send him "a rar file" or you just need a good archiving software? Download and install WinRAR.
If you want to put your video files online using HTML5 then it's recommended to have three different formats for a full browser support. Those formats are mp4, ogv and webm.
VMware player is a great free tool for creating virtual machines and desktops. For instance, you can create a new virtual computer to install and test the new Windows 8 Consumer Preview.
If you use a lot of different usernames and passwords it is difficult to remember all of them. KeePass is an interesting solution where all your passwords are kept in one safe place and protected with one password.
If any file can not be deleted, then you can use the program LockHunter, which removes the active connections of other applications to that file, which allow you to change or delete file.