Laptop keeps switching off!

Got a call this lunchtime from a new client - funnily enough, while he was getting off a bus!

Anyway, he said his laptop kept turning off - unasked. Sometimes it might last an hour or two and other times, it would turn off four of five times in a morning. As you can imagine, this was very inconvenient.

I had three or four thoughts.

• Power supply - sometimes power supplies get damaged or the wires get worn and the output is not what it should be. Generally, they will just fail but, I guess, there could be cases where it carries on going just enough to power up the laptop but not enough to keep it going.
• Power options - in the Control Panel, you can set what the laptop should do to save energy. I figured that these might be set ridiculously low or something. They are unlikely to act irregularly but worth checking.
• Fluff in the fans! - this was high on my list. People often sit the laptops on cushions, on the sofa or on the floor where the air intake can suck up dust and fluff. If enough gets in, it can reduce the efficiency of the fan resulting in overheating. If the CPU gets over its maximum working temperature, the BIOS will just turn it off to protect it. To contain the problem, laptops generally have a fluff filter on the way into the fan, so all that is needed is quick bit of housekeeping. However, there was a particular Dell laptop - I have forgotten the model - where the fluff filter was after the fan. So the fluff was sucked in by the fan and then couldn't escape! All that could be done was avoid putting it on the floor or cushions. It was fiddly getting all the fluff out but it worked fine thereafter.

Anyway, when I started checking these, they all seemed fine. The fan entry and exit were completely clear of muck. The power supply seemed absolutely fine. The battery was fully charged - so the power supply was obviously providing enough energy to run the laptop AND top up the battery. And the Power Option settings were fine.

A bit of head scratching followed, followed by a bit of shuffling of the laptop on my knees as, without noticing it, it was getting uncomfortably hot. Unconsciously, I had moved it to allow my knee to cool down. When I noticed what I had been doing, I checked the CPU temperature. They were showing 89°C - uncomfortably close to its maximum temperature.

Since it wasn't a fluff in the fan problem, the next places to look are other hardware and software. Since the fan appeared to spinning all the time at full speed, I checked what the CPUs were doing - Task Manager showed they were running at a high operating load - 80% and above. There was nothing to show in the Applications tab so I checked the Processes.

And there was a likely culprit - Google Desktop Search was running at 50% of CPU! For these of you who don't know what it is, it is a search engine that indexes, potentially, the whole of a PC's files, not just for file names but also for content. So, not only can you search for shoppinglist.doc but you can also search for butter or eggs or whatever was on your shopping list within the shoppinglist.doc document. Similarly, it can even index the contents of all your emails. It can be a lovely tool to have available - providing (a) you don't index too much and (b) your CPU can take the strain. This one couldn't.

Since the client wasn't there, instead of uninstalling it, I merely turned it off, rebooted and rechecked the temperatures.

Within a couple of minutes, they had dropped from nearly 90°C down to below 60°C - much more comfortable on my knees.

So, I don't know that I have fixed his switching-off problem but I bet I have.