A few years ago I ripped my CD collection into MP3 format.  Along with songs I've also collected from other sources, I have thousands of tracks stored on my computer.  Trouble is, if I want to play a collection of songs I'm continually having to adjust the volume control, because some are much louder than others.

This isn't always a problem if I'm at home, but can be awkward if I'm in my office.  I need to keep the noise from the speakers low, so as not to disturb people in neighbouring rooms.

If your MP3 collection has a similar problem, try a program called MP3 Gain.  You can get it from http://mp3gain.sourceforge.net/download.php and it runs under all recent versions of Windows (32- and 64-bit).  

The program is free, and VirusTotal assures me that it's clean too.