Hie...i bought a second-hand Zanussi frost free fridge freezer on sunday.. i only turned it on, on tuesday after a thorough clean. the light goes on but its been 24hours and its still warm. infront is a round thingy, with number 1 to 6... its on 5 at the moment. then on the inside is a "cool flow system", ranging from cold to coldest....the knob is set in the middle.... im thoroughly confused and worried.

SOURCE: fridge making a purring sound then stopped working

Yes, I think you have a problem that can be fixed easily by a repair technician. The sound as you described it could have come from the air circulation fan in the freezer compartment striking ice. As the ice builds up it could have stopped the fan from rotating and air flow to the refrigerator compartment.

SOURCE: freezer very hot at the back

It is usual for the back of a fridge or freezer unit to get hot at the back as it uses a thermal transfer or heat pump process. As a freezer tends to cool the inside much more than a fridge it will obviously get hotter.
Make sure there is sufficient air flow around the rear of the unit and that no one can touch the rear radiator element, (to prevent burns.)
More expensive freezers actually use a fan to help circulate air around this rear element.

See http://uk.danfossuniverse.com/page2072.aspx for a more graphical demonstration of the workings.

SOURCE: Freezer not freezing!

try plugging the electric cord into a receptical

SOURCE: fridge warm

Do you hear the compressor running? If so you may have a bad defrost timer, causing the evaporator to freeze up, and therefore your poor cooling. If you do not hear the compressor coming on then it could still be a defrost timer issue (stuck in defrost) or it could be a more serious problem that will need to be tackled with a voltmeter and a clamp on amp meter. (checking @ compressor)

Hope this helps