My name is Mike, I’m a Technical Analyst located at Dell corporate headquarters in Round Rock, TX. I’m part of an internet outreach team developed to interact with the online community regarding technical questions and issues that customers face with Dell products. I’ve read about the problem you’re having and wanted to offer some help.
First, if possible, get to the desktop and open the “Run” box from the start menu or by pressing the windows key and “R”, then type in “shutdown –a” without the quotation marks. This tells the system to not reboot or shutdown in the event of a fatal system error. If this doesn’t work, try booting into safe mode by tapping the <F8> key when you see the DELL logo at boot. This will put the machine into a simple boot mode with no extra drivers then those needed to start the machine. If the problem happens in safe mode as well you may have a corrupt Windows file and you may need to reinstall windows. A guide to help you do this can be found here: http://support.dell.com/support/topics/global.aspx/support/dsn/en/tree?c=us&l=en&s=gen&journalid=&treeid=188B8BFD1A2CBED4E0401E0A5517180F&Query=&SystemID=&ServiceTag=&contenttype=&os=&component=&lang=&doclang=EN&toggle=&dl=.
If the problem is heat related then you will notice the system shutting off without having to open any programs. You will also notice that the amount of time the system stays powered on is reduced with every reboot. In other words, you turn it on and it shuts off in 5 minutes. Then you turn it back on and it shuts down in 4.5 minutes, then 3 minutes, then 2 minutes, etc... The system should also give you a warning message saying it was shut down due to an unexpected thermal event. If it only happens when you open an application though I don’t think it will have anything to do with overheating.
Memory may be a possibility, but usually it will give you some kind of error or it will just blue screen out with a memory error. You can check the memory by using the online teardowns found here: http://support.dell.com/support/topics/global.aspx/support/my_systems_info/en/manuals?c=us&l=en&s=gen and remove one of the memory modules (if you have 2 or more) leaving only one memory stick in the system. If it does the same thing try moving that stick of memory to a different memory slot. If the same thing happens again, try the same technique with a different memory stick. If it continues to do the same thing regardless of which slot the memory is in or which stick of memory is installed then the problem more then likely isn’t with the memory.
I hope this information is helpful.
Dell customer advocate