Toshiba Satellite 1805 S204 Shutting down randomly

[Nitin]

Dear Friends,
   Hello This is my first post . Big thankyou for reading  frankly you guys are my only hope of saving my favourite laptop.
I have Toshiba satellite 1805-S204 for more than a yr (1g Celeron, 256MB, 16 MB trident video, DVD, Floppy ) Running Windows XP & Red Hat Linux 8.0.

Problem is after a recent travel the lapop is shutting off randomly. i.e it turnon  then shut off after a while (15 to 20 minutes). Also I cant hear Fan's noise.. may be fan is not working !! just my guess. & bottom of the laptop is very hot !!

Can anyone tell me what can be done to resolve the problem. I gave laptop to a local repair shop who charged me 100$ and then cooly told me there is nothing wrong with it !!!  

Hoping for a good reply
Regards
Nitin

[query]

The fan cycling is normal - it runs only when the temperature is too high.

Turn off the auto shutdown/reboot (under Advanced in the system applet) -- see if you get a blue screen that might identify the culprit.  Also examine the event logs (under Administrative TOols) to see if anything shows up there.