Used Motherboard/CPU

If I were to receive a used CPU/Motherboard combo off of someone else in the clan, would I run into any issues? I already own a 600w corsair power supply along with an AMD HD7870 ghz and I plan on receiving an i7 2600k from a clanmate along with a compatible motherboard. The rest of the parts I would purchase off of Newegg. Would there be any problems that I would run into?

as long as the motherboard and processor are compatibile then no you wont have any issues

And as long as you don't have a pretty standard setup 600w should be enough to power the hardware that you have listed.