when my laptop gets really hot (hot enough to really hurt) my cpu fan rarely turns on. so i know the fan is able to run.when it does turn on it kinda ramps up then turns off then ramps up again then turns off for a while then it will do it a few more times. my laptop hasnt overheated to the point of turning off yet but it seems like its a preety big problem.
i have tried using Speed Fan to manually turn the fan on but it wont turn on. i have opened it up and tried to see if it is a loose cable but all of the cables are fine. im all out of options so i came here.
Laptop: Toshiba satellite L955-S5370N
OS: Windows 8
1| Can you take a look at your temps with HWMonitor?
2| Make sure that your laptop is on the latest BIOS revision.
3| When you opened up your laptop, did you inspect the cooling fan t see if any dust, debris or hair follicle was impeding the fans movement? I dealt with a unit of similar nature, only that it stopped moving due to collection of debris(lot's of it!).
4| While reassembling, make sure the screws aren't tight but that they aren't loose enough to rattle out of their places either.
On a side note, are you talking about the under side of your laptop getting hot or the place where you rest your hands to type? It's quite possible that your HDD is dumping heat due to age/ware&tear. Afterall the processor you have is rated only at 17W TDP.