If you are having no other issues, the shutdown is probably related to heat.  The heatsink is likely covered with dust.  If you use a can of compressed air to blow through the heatsink in the reverse direction you might correct your problem.  If you have never done this, however, the dust could require disassembly of the case to clean the dust manually.  See this:

http://support.dell.com/support/edocs/systems/smrt250n/

Unless you are comfortable doing this yourself you might want to consider taking it to a computer repair shop.

Good luck!

http://bellsouthpwp.net/t/w/twinhill/200NHeatFix.html

http://nfn15037.tripod.com/


try either of these to help with your problem. sounds identical to what was happening to me. i sent my laptop back to dell 4 times and they replaced everything saying they fixed it. I finally opened it up myself and there was no heatsink compond on the processor just a small white rubber pad.... well duh rubber doesnt transfer heat very fast. slapped some silver heatsink on it and presto!!! havent had anymore issues in 2 years of using it all day everyday. i do everything from work, video streaming, conferencing, video games, watching dvd's, i even got a tv tuner card for it, i watch all my tv on it. so yeah i run it all the time and it never tops 120degrees F. check out a program called everest home edition produced by lavalys. you can actually monitor the temp of your processor and video card with it.

Same problem as extensively reported elsewhere regarding overheating and frequent shutting down on the SmartPC 250N.  Having attempting solutions using compressed air I have dismantled my laptop.  The heat sink and associated components were clean as was the cooling fan although it does appear that the aperture on the inlet side of the fan is restricted by adjacent components

As this appears to a common fault perhaps it is necessary to press Dell for a permanent no cost solution

been there... done that... doesnt work. I have spent a total of just over 37hours on tech support with dell. sent my laptop back to them 4times within 8months. they replaced everything over and over again saying there was no problem with it. they even upgraded my processor to a faster one for free. dell refuses to admit there is a design flaw with there smartstep laptops and will do nothing about it. There was even a list started by a gentleman on the forums whom had hired a lawyer and had a list of a couple thousand people with all the same problems, but that fizzled the minute they got started with the court systems. so we all just gotta deal and live with our mistakes of buying 'smart'step laptops from dell.