>---
>An internet mischief maker has built a USB stick that delivers dangerous
>220-volt shocks to PCs, destroying them in the process.
>---
>There is a link to russian blog from 8.oct.2015.
>In some thread here, jim bell wrote something like patched microwave
>oven can focus "energy" remotely.  Does this method, if applied to
>desktop/laptop damages them remotely?

A typical microwave oven is a 1-kilowatt source of 2.45 GHz radio signals, generated by a device called a "magnetron tube", which is itself fed from a source of about 4000 volts and 0.3 amps, stepped up by a transformer from the AC supply.  Usually, the  power is fed into a box with metal walls, which is easy, but has a front door which is easily closeable yet has excellent shielding ability when closed.  Such microwave ovens are carefully designed so that they will not generate microwaves when the door is open:  To do so would expose the user to microwaves far above the safe level.  

Now, if your intent is to do damage, you could bypass the safety features of the door, and partly disassemble the oven so as to feed the as-generated microwaves into a waveguide (sometimes it's a hollow rectangular tube) which proceeds to the antenna, which is often at the focus of a parabolic dish.  Generally, the rule is the larger the dish, the more focussed the microwaves will be.  An 8-foot diameter dish would be excellent, perhaps giving 30 db of gain over an isotropic.  There are formulae for calculating gain vs. dish size vs. wavelength easily found on the web.  https://en.wikipedia.org/wiki/Parabolic_antenna   or the Radio Amateur's Handbook.

However, for REAL damage, it would be useful to pulse the kilovolts into the magnetron:  Generally if you increase the voltage by 10, the power increases by 100.  Feed that microwave magnetron with brief (microseconds) pulses of 40,000 volts, rather than 4000, and it will probably generate close to 100 kilowatts.  It would be necessary to establish that such a system will not arc with over-voltage, either within the waveguide or the associated high-voltage wiring.  Much of the electronics within a building would be fried if such a beam is pointed at it.