Break Reminder is a program to help prevent OOS/RSI and to assist in the healing process if these or similar conditions already exist. It boasts a small interface that discretely runs in the background monitoring your computer use, which uses timers (to your settings) that remind you to take a break.
Break Reminder is designed to both prevent and assist convalescence of these debilitating computer terminal associated conditions. It has numerous other benefits also. Whilst the developer has many anecdotal reports of the value of this software, there is also research that supports the value this type of software provides to PC users.