MB Screen flickering???

So, My brother's MacBook's screen keeps flickering. But's it's only at first, it's like once it warms up it's fine. I've hear it could be resolved with reseting the PMU...? How can you reset the MB's PMU?

Thanks in advance,
iMacKid500

Sometimes this works, but it's always only temporary. I am convinced this is a hardware fault, caused by poor power management... but that's just me.

Take it back and ask for it to be repaired. I've had my flickering screen 'fixed' twice; they replaced the inverter. One more time and I'll be asking for a new machine.

To reset the Macbook's PMU, shut it down, remove the battery and hold down the power button for at least 5 seconds. Then replace the battery and restart.