Alarm, Calendar Magic, Free Alarm Clock and VisiTimer are some of the most popular free alarm clock applications for Windows. All of these applications are available for download on CNet.
Alarm is a very straight forward application that allows users to set a message to display and sound to play at a designated time. It offers both a.m./p.m. time and 24-hour time display options. It also features customizable snooze intervals
Calendar Magic is actually an application for calendar management. However, one of the features is a simple alarm clock that can be set for any time. Alarm offers functionality to repeat alarms as well as choose different sounds to play when they go off.
Free Alarm Clock is one of the simplest to use options as a pure alarm clock. It features the ability to set multiple alarms and choose when to repeat them. The software is also able to wake up a computer if it is asleep and turn up the computer's volume if it is low or muted at the time of an alarm.
VisiTimer offers much the same features as the other applications. However, it has a countdown timer feature in addition to its alarm clock functionality.