ok so my amd stock heat sink came with thermal paste applyed on it but i had to takeit off the cpu twice . so will i have to put more thermal paste on it befor i accually start running my pc how important is it to have a new coat of thermal paste ? it still has it on it its just spread out
If you don't have any it's ok to keep using it but it's ideal to apply again.
Clean the old paste off both the heatsink and CPU with coffee filters and acetone like Nail Polish or >90% Isopropyl, and then put a dot sized drop of thermal paste on the CPU center and press down the heatsink and install.
Good pastes are NT-H1, TX-2, G751 Shin-Etsu, and if you care for the exotic stuff, IC Diamond 24-carat, and CoolLabratory are good.