ARDUINO MEGA VOLTAGE GOES TO 6.5V

I AM USING ARDUINO MEGA 2560 WITH ETHERNET SHIELD FOR ONE PROJECT .THE VOLTAGE AT PIN 5 GOES ABOVE 6V AND ARDUINO STILL WORKING BUT THE ETHERNET SHIELD MALFUNCTIONING . HOW TO REDUCE THE VOLTAGE PLEASE SHARE ME. I USE ARDUINO MEGA AS SERVER TO CONTROL RELAYS USING DIGITAL INPUTS OF 5V . THE RELAY OPERATES AT 7.5V SOURCE BOTH GROUND ARE CONNECTED. I MEASURED THE GND PIN AND 5V PIN OF ARDUINO IT SHOWS 6.5 V

Hey, turn off the CAPS lock, that is hard to read.

Anything above 6V will damage parts.
How are you wired up? Are you trying to use Arduino to control a relay with 7.5V on its coil? You need a transistor there - the arduino controls the transistor, the transistor sinks the coil voltage.

Like so.