Mine is 7 years old. I had an issue where it wouldn't stay down, or heat even if I held it down. No power at all.
Firstly unplug it.
To take it apart, turn it upside down. You have to get the 4 security bolts undone which are underneath (Mine look like they have six holes around them). I have a set of security bits from Maplins. While none of these fitted exactly, I managed to use a size 10 double prong bit to get it partially undone, then when it was protruding enough a 4mm socket.
Also, you need to unscrew the bobble by hand which you use to push the toast down. You can then pull the cover off, from the back first. The timer dial is connected to the cover, but I didn't disconnect this.
Note: You don't need to undo the bolts inside the toaster. (They only hold the metal base to the plastic base), the 4 torx screws holding the side panel on, or the 4 twisted pieces of metal which hold the toaster internals to the base.
Inside, there are 4 prongs which are pushed together when you push the toast down. On further inspection, I found the main blue power cable had become corroded, and had melted and become disconnected. So simply unscrewed the 2 screws hold this section on,(simply for easier access) and resoldered the blue cable back onto the correct prong.
And now it works again!
Steve Bates, June 2010