My Toshiba P35-S611 shuts down without warning a short time (2 min-45 min) after it boots up. The battery isn't hot but the heat dissipation fins in the back are very hot.

Indications of laptop overheating problem:

1. The keyboard and the bottom of your laptop are very hot when the laptop is working.
2. The CPU fans are working all the time at maximum rotation speed and operate much louder than before.
3. The laptop suddenly shuts down by itself without warning. When it just started, the laptop was shutting down after 1-2 hours and how it shuts down after 5-10 minutes of operation.
4. The laptop works fine when it runs idle, but shuts down as soon as you start using any memory demanding applications (DVD player, image editing software, video editing software, etc.).

1. Open the laptop case, so you can access the CPU fan and the heatsink. In some cases you can access the heatsink through the latch on the bottom of the laptop. Sometimes (for example Toshiba Satellite A70/A75) you have to open the laptop case all the way down.
2. Carefully disconnect the fan cables on the system board and remove the fan. If the fan makes unusual sound when it spins (grinding sound), I would recommend to replace the fan.
3. Clean the fan and the heatsink with compressed air.
4. I would also recommend removing old thermal grease from the CPU and applying new grease for better heat conductivity.

Yup. Its the heatsink cloged with lint and dust. I took my p35 apart removed the heatsink cleaned it and the fans then removed the old thermal paste and replace it with "Artic Silver 5 " Thermal paste. Put it back together and Ive never had a problem with it shutting of since. The fans run nice and slow all the time now unless im runnig a big application . Even when running a big progam or application the fans never run on full like they use to. They come on full for like 3 seconds when you first turn on the laptop and then ren slow, but this is normal.