Playing a wizard. Have hardly had any actual go out and kill mobs type quests. I get a quest to investigate this dead body and it spawns this boss, Red Nose Blah or something like this. So from go kill 10 imps and 10 wolves to trying to kill a tough boss.

I can't even come remotely close to beating this guy. Not even close. My skills register almost no damage to his health bar. After literally 30 minutes of running around I have to give up. What am I doing wrong here? Somethine seems way off here. This quest seems to be blocking me from getting other quests so I'm pretty much stuck until I get it done.

Might want to go kill trash mobs around there for a while and level up some more first, which will open up some more skills and skill levels for you.  Not a lot, but some.  At level 20 you can start getting other quests from NPCs (go to quests settings and select to show all).  Some of those may also help with gear a bit.

The old Rednose boss used to be ridiculously easy, but was actually more appropriate for a brand new player.  This new version, which also has capped stats (I think), is a bit much for that level.  Not sure what other new players do for it. I am curious about that.

Hello new adventurer,

Just so you are aware, there are bosses that belong to the special "rift" spawns. These "rift" bosses appear at random in a few locations in the early game areas. They are not to be beaten with a low level character, they belong to the level 56+ power level. 

It is possible that you are confusing this "rift" boss with the one you are tasked to defeat in your mission log or quest log. Please follow your quest marker to the boss that should be highlighted when you right-click the quest log window.