Want to keep a laptop around for a long time?
Fully discharge the laptop battery and remove it.
Put it in a shielded cage, as described by kernelkrink, above.
For the "Oh well there's no power." crowd...
Get a car alternator and a bicycle, now you have a 12VDC source... guess what, most laptops run on 12VDC. Buy some solar panels, they're not extremely expensive any more, some even put out .. you guessed it .. 12VDC.