This started happening after I finished with the Boomers. I have to return to Mr. House and finish his quest but every time I enter the Strip the screen goes black and it locks up. Only choice I have is to run around doing other side quests. I've tried going in many times and no luck.

i've got the same thing. pretty much kills the game there and then. i've tried going back through my saved games with no luck.

guess i'll have to start the whole game again and hope it works a second time.

I may do that and just screw around. I'll wait for a patch and then return to the Strip.

http://fallout.wikia.com/wiki/Debt_Collector

Check the bugs part of that page, guys, because it sounds like that...

This bug has been confirmed and it's horrible... Hopefully they fix this in the new patch...