7 years old !!! Time for a new one.
Heresy! Whilst I can appreciate the urge to replace and renew equipment at the first opportunity, for me if something 'just works' it's often less trouble in the long run to keep going. I too have an 'ancient' MBP that has been pimped up a bit and it still does a sterling job for my needs. The software does seem to be pleasing less sites, due to them upgrading their systems and configuring them towards the newest OS's, but I c an hold off spending over £2K on the newest steed for a while yet ;-)
To the OP, please let us know what the geniuses have to say. I hope that it's not the logic board which often renders the repair angle dead in the water.