We just got a second hand spa that had been stored for about 2 months, and when we plug it in, nothing comes on. the control panel doesnt light up.

Did you check the fuse on the control board?

MY control panel was replaced ,it cycles but, no lights ,no jets,no heat works..What's the problem .

look like shorted out cluster (intrument panel) get a second hand one its cheaper or body control module when it does the car dont start or goes good if it doesnt start bcm if it run bad cluster good luck pierre

check wire going from out door panel to indoor panel.if this doesnt work tou need a new board.

If it only 6 month sold send it back to the store you brought it from as you should have a 1 year warranty with it. The other thing is when you switch the computer on does the power light come on and nothing happens? If so then the CPU could be out of it's socket slightly which this will have nothing to do with the power supply.

I suggest if you have had it from new send it back to the store if you purchased second hand open the cover detach the CPU fan and lift the release lever and push down on the CPU and close the release lever then replace the CPU fan and cover then try switching on.

Hope this helps you
Cheers J

which 2 buttons flash?

The manual indicates this means that it is time to decalcify the machine.  After doing so, press the ON/OFF and PROG buttons at the same time for 2 seconds.   Jeff, Burbank CA