How can I fix my power button?

At the very least you'll need to remove the cover that has the On/Off Button on/in it. Generally this involves opening the unit and lifting the plastic cover after removing any screws on the back of the hinge.

When you get the cover off it may be full of Gunk and just need cleaning or the Micro Switch under it may be broken or maybe even the Circuit Board.

No matter what you need to replace the Circuit Board and Micro Switch Assembly which you need to buy from Toshiba and here is the problem.

Toshiba doesn't play nice with it's customers or opposition. If you want any Service Manuals or Parts you are fighting an uphill battle as Toshiba doesn't sell these things. If you are in a small Town you may have an Independent Toshiba Service Agent who will sell them to you but most times you have to take the unit to a Authorized Toshiba Service Agent and pay them to fix it.

Col