Computer keeps shutting down for no reason

Is it a laptop? Is it excessively hot? Perhaps your computer fans are clogged up with dust/hair/etc and the internal temperatures are too excessive. If so, it will automatically shut off so that it doesn't fry the computer.

more information, please.

Most probably heating issues

help us help you by giving us more info.

Your hard drive has too much bad sectors? We need much more information.

  Cindy. Welcome to the forums.

Cindy, what everyone here is telling you is that we need a lot more information.

First of all, there is a reason it is shutting down. We just don't know what that reason is.

Here is a list of things that may help us:
Laptop or desktop system?

If desktop system:
Configuration (what parts are in it - motherboard, memory, PSU, video card, case)?

Is it stock, overclocked, or does it contain special hardware??

When did the problem start?

What are you doing when the problem occurs?

What software is running when the problem occurs?

Is the problem repeatable?