Every 10-15 minutes, a computer in my house has a Thermal Event. It just shuts down, and when you start it up it gives you the Thermal Event error and to press F1. It is a STANDARD DELL Dimension 3000, with 512MB RAM, 70.9GB Hard Drive space, and it's been doing this for months.It sounds like the computer is overheating and SHUTTING down to protect the hardware from damage.
Step one is to CLEAN out the inside of the computer case.
Turn off the computer, open the case and use a can of compressed AIR to blow out the dust.
Make sure to clean fans and heat sinks as they are important when it comes to keep the computer cool.
A few words of warning when cleaning your computer:
1.) Remember to TAKE anti-static precautions before working inside the case. You can discharge yourself of any static electricity by touching a piece of grounded metal.
2.) Do not use a vacuum cleaner. They can generate huge amounts of static electricity.
3.) When blowing the fans clean do not let them spin. Hold them gently in place.