Main Power Board

My 6 yr old set has been diagnosed with a bad Main Power board.
Gateway wants $250 for the part. Can a lay person replace the board?
Can I just take off the back and plug in the new board?

The power supply board can be changed without any knowledge of repair but there are sometimes adjustments necessary if the picture is not normal. Many times it is fine. There a 4-5 voltage adjustments that would take some knowledge and a meter to accomplish. You need to hope it was diagnosed properly first. If it is completely dead the p.s is a good possibility. If it clicks on then back off almost immediately it is not likely the power supply.