In response to the previous few posts in this thread, attempting electrical work in the home if you are not an expert is potentially dangerous. There are a few no doubt well meaning posts above suggesting home brew solutions made by people who perhaps know what they are doing. But suggesting such a course of action to someone who does not have the prior knowledge, training and skills to do such work is utterly horrifying
Please, don't fiddle with this stuff, call an electrician. Even call the electricity company. In most countries they will do a free safety check for you and give you advice about what might need fixing.
For starters, if the voltage between neutral and the yellow/green wire is 126 V, then that is not a proper earth wire and you should not trust it. Stop here and get expert advice.
Also, it is important to be aware that the electrical installations in different countries may be very different.
In (some or most) Norweigan electrical installations the normal 230V loads are connected between two different phases of a 3-phase 230V supply. If the supply is perfectly balanced you'll have 133V (that is, 230V/sqrt(3)) between phase and ground as well as between "neutral" (which is actually another phase) and ground. Measuring 126V would be perfectly normal!
At least here in Sweden, having only ungrounded receptacles in some or most rooms is very common, and I suspect that this goes for other Schuko-using countries too. Grounded plugs fit in ungrounded receptacles, and the idea is that since there are no grounded items in the room you are safe as long as you don't touch two different defective appliances at the same time (which can be classified a double or even triple fault). This is no less safe than ungrounded non-doubly insulated equipment which relies on the same thing to get its second safety barrier. The plugs of this kind of equipment do not fit in grounded receptacles.
In new installations grounded receptacles are required, to which non-doubly insulated ungrounded equipment can not be connected. New equipment is required to be either grounded or doubly insulated. Doubly insulated equipment has plugs that fit in both grounded and ungrounded receptacles.
So, in the Schuko system you have the following kinds of receptacles:
ungrounded receptacles in rooms where the room itself is insulating (not used in new installations)
grounded receptacles: in rooms where ground is accessible, outdoors, kitchen etc. or recently everywhere
receptacles into which only doubly-insulated equipment can be connected (pretty uncommon)
Mixing ungrounded and grounded receptacles in the same room is not permitted in Sweden because this would introduce ground into the room, whose absence is relied on as the second safety barrier. (a Finnish poster earlier in the thread said the same thing applies for Finland) The receptacles into which only doubly insulated equipment can be connected can be mixed with the other kinds. They can be used in a room where ground is accesible, without requiring a ground wire to be available for the receptacle.
As for equipment and plugs there are three different kinds too:grounded (fits in ungrounded and grounded receptacles): relies on the ground as a second safety barrier
ungrounded (fits only in ungrounded receptacles): relies on the insulated room as a second safety barrier.
doubly-insulated (fits in all receptacles): the second safety barrier is internal to the equipment.
Note that the way different plugs fit into different receptacles is opposite of that in the US, unless nongrounded US receptacles and plugs are understood to correspond to the doubly-insulated Schuko ones!