Powering up several devices from one charger
At 12 V DC, 50 W means that it will draw 50 / 12 = 4.17 A. Multiply by 4 and you get almost 17 A. Let's provide 1 A for both fans. This means you'll need a power source that can supply 12 V at 18 A (a total of 216 W output power).

A laptop charger usually supplies 19 V at 3 to 5 A. So it is useless.

If you can get one, a computer PSU may be good for this. Just make sure the current on the 12 V rail is greater than 18 A and add a dummy load (resistor) on the 5 V rail to get it working.

Another solution is to buy from your favorite electronics parts supplier a SMPS kit with those ratings (12 V @ 18 A output).