Remote self distruct button.... soon as it powers on and connects to the net *bang* ^_^
The thought that someone would just sell it! Can't you put some type of legal clause to stop that... If first prize ends up on eBay the next day shame on them.
If I won it, then I would give it to my dad to upgrade him from a 2500K, 8Gb ram and GTX660 and then sell his old bit's to allow me to upgrade my pc.
Wouldn't dream of selling the prize pc simply because it wouldn't be fair to those who entered the comp and didn't win.
Maybe TTL could add in the T&C's of the comp to try and avoid that from happening.