オリジナル投稿者： Puru ,
Okay seems like nobody answered you to help reset PRAM or NVRAM since it's particularly the issue over RAM replacement. Here's how? # Shut down the computer. # Locate the following keys on the keyboard: Command, Option, P, and R. You will need to hold these keys down simultaneously in step 4. # Turn on the computer. # Press and hold the Command-Option-P-R keys. You must press this key combination before the gray screen appears. # Hold the keys down until the computer restarts and you hear the startup sound for the second time. # Release the keys. Your computer's PRAM and the NVRAM are reset to the default values. If any PRAM or NVRAM congestion was causing such issue, it should have been addressed by this attempt. Cheers!