I have to do a mission to go inside the lucky 38 and get mr house out of the war it says i need a key to get in there. can anyone tell me what to do?

Talk to Victor in front of the Lucky 38. He'll hook you up.

Did you read the question i cant get into the strip.

It's a bug, reload an earlier save.

It happens, I got locked inside the brotherhood bunker on one of my saves. It svcks, but it happens.

sh1t i have to reload a save i leveled up 3 times and...... damn god f'ing damn it

This also happens.

Consider yourself lucky you just have to redo 3 levels and your whole save game isn't F'd.

I have never had this bug. Do you have the 2000 caps to pass the credit check? If not you can buy a passport from Mick and Ralph's.
I have also heard you can kill a securitron and take his key if you have the muscle.

Go through Camp McCarran and use their monorail, just take a NCR Armor outfit with you.

Go here
http://fallout.wikia.../wiki/The_Strip