There is a kind of way to do it, but it involves a shed load of electronics, a chemical bath and a few other things. And it's definitely not alchemy.
Basically, most decent electronics have circuit boards and components that contain gold, platinum and all manner of precious metals. By subjecting them to high temperatures and/or a chemical bath it's possible to separate the various metals to a greater or lesser degree. The amount you can actually strip out isn't really that much, so it's only really profitable if you have access to a large supply of materials to strip and a process that is relatively automated, because it's not a 5 minute job and pretty dangerous (gases and other nasty shit will build up).
Having said that, there are people that do it as a hobby, but most of them will freely admit that the time, effort and cost will barely be covered. You can't just lob a circuit board in an acid bath and get a gold bar. The most you'll get is about £1 of precious metals from a circuit board, but that's if you can get it to maximum purity.
There's also the fact that it would be highly improbable that a motherboard would sell for would sell for £500, but contain anywhere near that amount in precious metals. If that was the case then places would just be buying the motherboards, recycling them, and profiting instantly. The prices of motherboards would rise due to demand, the prices of the various metals would crash due to the amount flooding onto the market, and before long a loss is made. In the case of gold this would actually be quite catastrophic because most of the currencies are based on gold.
So it can be done with science, but isn't worth it unless you can do it on a huge scale.