WinRAR is an archive program designed to open archive formats such as RAR. These files store other files within themselves in order to compress and store them for easy transport. If you have a password-protected RAR file, you'll need to input the password before you can open any of the files locked inside. In case of a forgotten password, you can bypass this problem by using some free software to locate the password and open the file.
Download and install RAR Password Cracker (see Resources). This program is free to use initially, and it costs $30 as of 2010 to buy and unlock full features. It uses the brute force method to go through every letter combination until it finds your password and unlocks the file.
Download and install RAR Password Recovery (see Resources). The free version of this program has a three-character limit for passwords. It uses strategies such as going through an entire dictionary's worth of words until it finds the one that matches your password.
Download and install RAR Password Recovery Magic (see Resources). Recovery Magic is free to use for 10 passwords before you need to buy the full version. It has custom controls that let you choose which sets of numbers, letters and symbols you want it to try on breaking your WinRAR password.