dell laptop turning off after a while

[simincc]

i have a dell vostro 1540 laptop windows 7 home edition.
for the first time it turned off after 2 3 hours of working..this happened 4 or 5 times again...i thought it was virus and wanted to re-install windows..but i couldn't because the time of turning off had been shorter that couldn't even start windows...i searched for this problem and found that i should reset my hard...when i did that it have been fixed for a day..but after that the problem came back...i didn't know if it is virus or software problem or hardware problem ..i don't know .....

[JorgeM]

It could be that the hardware is overheating. Do you hear that fans moving properly? can you open the computer to verify that you dont have a fan partially spinning or some other obstruction? It could also be that the heat sink over the CPU is full of dust, not seated well, etc..

[diprofinfiniti]

How old your machine ? if more than a couple of year or more, probably it caused by dust in the cooling system. Be sure your laptop being serviced every one or two year usage.

[caperjack]

Be sure your laptop being serviced every one or two year usage.

i agree with this but i would shorten it to 6 mnt to 1 year ,depending on the dust in you home