Computer Stopping Randomly

Currently I have an E-mail system set up and it uses the os.pullevent() function. When i run the computer it works great. However i will go somewhere else and come back and it has stopped!!! i have never caught it in the act. Why does it do that?

Computer Craft 101

Computers shutdown when unloaded form the world. This happens when you walk a long distance away from the computer. Computers that were on will start up when reloaded into the world (when you walk back in range).

A computer with a file named "startup" in its directory will run it every time it boots.

Solution

Rename your program startup

if you cant rename it (for some reason) then there is a second solution ask for it and I will explain it is a little complex.

Second Solution: Use a chunkloading mod

Or just add a shell.run() entry in your startup so that it will run on startup. No need to rename it to startup.