PSU issue?

So I just acquired a new CPU which is a AMD 965 thanks to Caddi Daddi. I am changing a few things when I add this to my rig. I will be adding a new HDD or possibly 2 and going to windows 7 64 bit. Will I need to change the PSU as well? I dont want it to be an issue. What would happen if the PSU isn't enough for the system? Thanks for your help in advance

Assuming that the Antec 500w PSU in question isn't one of the garbage-capacitor units, it'll be just fine with your new parts.
What's the model name and/or part number on it?

Even if you OC the Cpu and Gpu you maybe would have a 400w power draw maxed out. The 500w unit should be good enough if it is actually putting out 500w. If it is an old unit you may want to play it safe and get a good quality unit but 500w is plenty.

So I installed the CPU along with a Coolermaster EVO 212 cooler and hooked everything up, however, the system wont turn on. I get a blip of power where my fans (LED) come on for about second and shut off with nothing after that. The only way it will give me a blip of power again is turn off the PSU and back on. These are the only changes to the system and i'm baffled. The system was on and running before anything was changed. The PSU is an Antec 500w earthwatts PSU. Thanks again for any info.