PC Chrono is described as 'countdown timer capable of .mp3, .ogg or .wav file playback on completion'. There are three alternatives to PC Chrono for Windows, Mac, Android, Java and Linux. The best alternative is Hourglass, which is both free and Open Source. Other great apps like PC Chrono are wnr (Free, Open Source) and Stopwatch (Free, Open Source).
Hourglass is the most advanced simple countdown timer for Windows. Just enter a time in just about any format, and hit Enter. Pause and resume Start, stop, pause and resume your timers. Finally an app that can do everything your kitchen timer can.
A Java countdown timer and stopwatch. Features a fullscreen and a resizable window mode. All actions are available on the popup menu or as keyboard shortcuts. Supports sound clip types of AIFF, AU, WAV and MIDI (uses the Java Sound engine)