I have a problem with being unable to enter the Vegas Strip. I'm currently on "The House Always Wins IV" I finished the Omerta task and before I went back to House I went out and did exp grinding for a couple hours. When I tried to return to the strip I clicked on the door in Freeside and it says "Locked, Key Required". Is this a bug or part of the quest? I never had this problem before. I'm playing on PC.

It's a bug. Open the console, click on the gate and type in unlock. Then save and restart your game, so it doesn't bork up your achievements.

Thanks.

does anybody know a way to fix this on the console? started a new game but would much rather finish my old one first.

Yes, Stand back as far as you can in freeside with a clear view of the securitrons through a scope. (Better if the rifle is silenced)
Take a shot at the securitron for a Sneak crit, make sure you're hidden. Loot the corpse for the key. Try again if they go hostile at you.

or you can use the monorail if it hasn't blown up.