Although you mention that you're using Vista, you haven't told us the make and model, age of the computer, desktop or laptop, which service pack you're using on Vista, etc.. The more information you give us, the better informed our answer will be.
Based on the symptoms you've provided, it could be a failed hard drive, which is the most probable here.. Or, maybe overheating causing the processor to shut down, or simply corrupted files causing the computer to shut down when it attempts to boot.
Just for grins, after starting the computer, immediately start pressing the F8 key, once per second till a selection screen loads.. Once there, use the up/down keys to select "Last known good configuration", then press the "Enter" key.. Follow the prompts and allow the computer tor restart itself. If the registry or other minor problems are the cause of your issue, hopefully it will start up and boot correctly.. If not, we'll need more information. But it still appears to be a hard drive issue.
Hope this helps.
Grif
My computer shut down by itself. When I try to start the screen comes on asking how I want to start. I click start normally. In about 5 seconds it shuts down. It won't start. I am running Vista. What could be the problem? Thanks
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