Acer Laptop keeps shutting down

lot's of possibilities, Either your laptop has Virus, or the processor over heating, means it will probably need to di-assemble and replaced heating compound.. called thermal paste..

try using a cooler pad for your laptop for heating issue,
try changing the RAM also sometimes the faulty RAM also does this

it may be one of the causes, but the main reason for it is the power supply keeps on fluctuating. You may call Acer for a possible replacement for it..

If the laptop shuts down after a period and won't boot up again until the laptop has cooled down, then the laptop has a thermal overload problem.
For instructions to fix this problem, please click on this link :-
Normal 0 http://www.fixya.com/support/r5959377-overheating_computer

1- Scanning computer to eliminate malwares, spywares and the viruses from your laptop.
2- Repairing and cleaning Windows registry.
These two tips are found to be very helpful to fix the laptop shutdown problem. Almost all the computer users surf internet which could result in viruses attacking your system. Some of these infections are really pesky and cause the machines to shutdown randomly.
The registry errors, however, are the internal errors and can become a cause of system crashes and freezes. The registry keys shall be in good health to keep a system perfect.
When I noticed my laptop keeps shutting down everytime, I tested the Intel Software Partner, RegInOut to fix the random shutdown problem with my laptop.

canning computer to eliminate malwares, spywares and the viruses from your laptop.
2- Repairing and cleaning Windows registry.
These two tips are found to be very helpful to fix the laptop shutdown problem. Almost all the computer users surf internet which could result in viruses attacking your system. Some of these infections are really pesky and cause the machines to shutdown randomly.
The registry errors, however, are the internal errors and can become a cause of system crashes and freezes. The registry keys shall be in good health to keep a system perfect.
When I noticed my laptop keeps shutting down everytime, I tested the Intel Software Partner, RegInOut to fix the random shutdown problem with my laptop.

increase ur ram Scanning computer to eliminate malwares, spywares and the viruses from your laptop.
2- Repairing and cleaning Windows registry.
These two tips are found to be very helpful to fix the laptop shutdown problem. Almost all the computer users surf internet which could result in viruses attacking your system. Some of these infections are really pesky and cause the machines to shutdown randomly.
The registry errors, however, are the internal errors and can become a cause of system crashes and freezes. The registry keys shall be in good health to keep a system perfect.
When I noticed my laptop keeps shutting down everytime, I tested the Intel Software Partner, RegInOut to fix the random shutdown problem with my laptop.

Hello, the major reason of laptop randomly shutdown is Overheating, you said it is not over heating...

I will suggest you couple of things that you can try:

1) remove the battery and plug the laptop on direct power supply, then place the laptop on a flat and hard surface and then boot the laptop.

or do a complete virusscan of the laptop.

or reinstall the OS...

It sounds like someone has suggested that overheating may have caused the random shutdowns (which is quite plausible). There are a few tools that can diagnose what is happening:

• Temperature: I use SpeedFan (http://www.filehippo.com/download_speedfan/) to discover the temperature of my cpu. My Acer 5630 is usually doing 50 to 60 degrees. Anything higher than that could cause the random shutdowns (I've seen it happen on other laptops). If you download this program, don't muck around with the settings (as it would advise you not to anyway), just look at the temperature readings (eg. core 1 core 2)
• I keep a cpu usage meter on my sidebar (http://gallery.live.com/liveItemDetail.aspx?li=587ef54f-e121-418b-b258-e583e105a0d6). It keeps an eye on the CPU usage so if i see it say 100% cpu usage then I suspect some software is inappropriately consuming resources.

Treatment of overheating would be to find the offending software and manage it or remove it. If it is not software at fault, then it may be that there is too much dust covering the ventilation (Your acer may be old and you may hear your fan increasing speed and the performance struggle sometimes). I opened up my one and found dust build up from the radiator all the way to the fan! (it was like around 1cm thick in some places, i wish i took a picture)
Another reason for random shutdowns is the integrity of the power switch or the lid sensor. My computer got rained on once and randomly shut down. It took a while of cleaning it with Circuit board cleaner from Repco (I had to open the panel that covered the power button and spray it). It got better everytime I cleaned it and now it reliably stays on (actually it randomly turns on now haha)

Return it for service. This is a defect. The fan should run until the heat is below the temp threshold.