I signed up specifically so I could address this issue.
I honestly don't know why they even bother to put a power switch on a consumer router, just unplug the thing. That's beside the point, though. Good news, your $200 brick can be debricked with just a little work, took about 5 minutes.
1. Remove the rubber feet from the bottom of the unit
2. under the feet, you will find screws, remove those. Note: doing so will void your warranty, but that isn't worth anything right now anyway.
3. Using a flat screwdriver, butter knife, sharpened penny, or any other thin, yet stiff, blade, pry the top away from the base. There are several catches along the edge, just pry them up and they will pop loose.
4. Remove the power switch button. It is sticking out, so you should be able to grip it with some pliers to remove it.
5. With the button and top removed, you can see the spring on the switch which is held on with a small piece of metal. Using a pair of pliers, remove the metal by pulling straight up. It is actually a small c-clip with the sole function of retaining the spring.
6. Remove the spring. You may need to remove the board from the base to do so.
7. With the spring removed, you can simplpy press the switch in and it will stay on.
8. Put it all back together. Good as used.
Game On
-Lonesouth