but what is a coronal hole
Had to search Wikipedia for that. It's a darker region of the Sun, where there is a lower-density plasma than average and it's colder than average as well.
Also it said that solar winds pass down them and that these can cause blackouts on earth is this different to a CME and a solar flare.
They are in fact different than CMEs and solar flares. Earth is protected by a strong magnetic field that protects us against most particles. Other particles are diverted to the polar regions of the world, causing beautiful auroras and geomagnetic storms.
In fact what is the difference between a CME and a solar flare
A solar flare often comes with a CME. It is a brightening of a region of the Sun, close to the surface. A CME is simply a huge amount of material from the corona that leaves the Sun like a giant 'blob', reaching Earth in some occasions. The first difference is the size; a CME is very large, while solar flares are very localized events. Solar flares occur near sunspots and it releases many kinds of electromagnetic radition, from white light to gamma rays.
