If you have cable TV service, it is likely you have run into some problem with the service at some point. No cable TV service is perfect, so you should expect some problems. However, there are certain problems you can solve simply by rebooting the box. This saves you the time it takes to call the cable company.
If your cable service is working but is having minor issues, try rebooting the box first. Cable companies send out packets of information, such as channel information and software updates, to the box every day. It is possible that there is a problem with one of the packets, which can damage the software in the box. Rebooting the box allows it to access fresh information from the cable company which is likely to fix the problem. If you have trouble getting the on-screen guide to work properly or similar minor issues, rebooting the box should be your first step.
If your box suffers sudden, complete failure, it may be a sign of a bigger problem. For example, it you suspect that it has been struck by lightning or has a short, you need to contact the cable company first. Do not touch the box.