I have started the skingrad recommendation but i have encountered a problem. I can find where Erthor is because one of the mages guild members that I have to talk to, to find Ertgor is dead so I can't continue the quest and get into the University to enchant my stuff. If someone could please help me find a way around this that would be great.

You can just go to the quest location and rescue him without being told where to go. You'll miss out on the Weak Fireball spell that way, though.

Assuming it's Druja or Sulinus Vassinus who is dead...

If you're on PC, use the following console command:

Setstage MG01Destruct 15

That will allow you to talk to Adrienne and the quest will proceed.