Bad Power Supply. Weak voltage power rail.
1) Acer's are known for low quality Power Supply's.
A) Low quality Electrolytic Capacitors
B) Low quality Rectifier Bridge setup.
C) Low quality MOSFET's.
D) Wiring that is used inside is too small of a gauge.
2) Dirt, dust, hair, etc., can render a Power Supply useless.
The Power Supply's used for today's computer are SMPS.
Switched-Mode Power Supply.
The cooling components are Heatsink's used inside, and an internal fan.
[ Typical construction of a Heatsink is a plate of metal with tall, thin fins protruding from it.
The plate of metal absorbs heat from whatever object it is placed against.
The tall, thin fins absorb heat from the plate, whereby they radiate the heat away.
If a fan is used along with the Heatsink, the air flow from the fan carries heat away from the Heatsink/s ]http://en.wikipedia.org/wiki/Switched-mode_power_supply
When the cooling components for the SMPS are clogged with gunk, (Fan and Heatsink/s), the cooling capacity drops tremendously.
Heat = Wasted Energy
The SMPS strains to keep up with the call for power, but eventually cannot, and hardware components inside fail.
The SMPS fails.
3) ALL of the LED lights on at one time use less than 1 Watt of power.
Each fan uses 2 to 3 Watts
A typical Processor can use 51 to 125 Watts.
Depends on the Processor.
The Acer Aspire M3201 uses different versions of the AMD Phenom processor.
Phenom X3 8650 (2.3GHz)
Phenom Quad X4 (2.2GHz)
Are just two of the AMD Phenom's.http://en.wikipedia.org/wiki/List_of_AMD_Phenom_microprocessors
Depending on the Phenom processor it can use anywhere from 65 Watts to 125 Watts.
With a bad Power Supply you can have enough power to light LED lights, and spin fans, but not enough to turn the Processor on.
No processor operating, No computer.
No computer = No video signal to the monitor.
Suggest you unplug the computer from power, (Computer off. Hold the Power On button in for a count of 10 seconds), observe Anti-Static Precautions, and use a can of compressed air for computers to clean the inside of the computer out.
Remove the Ram Memory module/s, ('Sticks'), and clean the gold plated contact pins on the bottom, with a pencil eraser. Remove the eraser dust with air. (Use a can of compressed air for computers if available, or air pressure from your mouth will be sufficient)
Reinstall the Ram Memory modules.
Plug the computer into power. WAIT 1 minute, turn the computer on.
Replace the Power Supply.