They do this deliberately so it will go faulty in a few years so you have to buy one (planed redundancy), my laptop is 4 years old and always had intermittent troubles and now it is working perfectly
Good to hear you have your lappy back. I would be lost with out my computers. I have sometimes noticed that they put a cheap sticker type thing that will work for a while but not very well in between the heat sink and the processor when I have seen that I always replace it with paste.