so, finally, after three weeks i'm up and running, and it's all thanks to the people on this forum who have busted their asses to do what should have been done in the first place.

as recently as yesterday, i was still unable to run the game, even in low settings with everything turned off.
the final fix? a combination of the dll replacement, upgrading all drivers - including my sound card - turning off vert synch for the mouse, and most importantly, disabling all non microsoft codecs.
whomever came up with that one, kudos to you sir.
i'm now playing on high settings, w/ everything turned on, and the game is running like a dream.
thank you so much guys.

how did you disable codecs?

http://www.gamesas.com/index.php?/topic/1133488-directshow-filter-codec-reset/

Let make this clear now. Malwarebytes Anti-malware (Paid Realtime) does show that File at Fallout New Vegas Nexus as containg a trojan - although Zone Alarm antivirus did not. I have come to trust malwarebytes because it has reliably found stuff that other antiviruses did not. Your call - Just telling you my results.


To be on the safe side - I went with a OS reinstall to reset my codecs instead of taking a chance on that program.

i used a different one - at work so i don't remember the name - that tested clean.
but yeah, disabling v-synch and disabling non-microsoft codecs seems to have done the trick for me.
but as the poster above said, these are third party apps, so you take your chances.