Having a very strange problem. Not sure what’s causing it or why.

Beginning two days ago, New Vegas has stopped responding to any and all keyboard/mouse input. I can’t click through the opening slides to the title menu, because the game doesn’t respond to keyboard presses or mouse clicks. It won’t even recognize Steam’s Shift+Tab overlay command. I have to use Ctrl+Alt+Del to bring up the task manager and quit New Vegas in order to get my mouse and keyboard control back.

I don’t have this problem with any other game, Fallout 3 included, and never had this problem with New Vegas until two days ago.

Anyone know what’s going on?

That's very odd.

I'd suggest backing up your saves and then uninstalling/reinstalling the game to see if that fixes it. I realize that isn't very insightful assistance but hopefully it's something that can be tried relatively quickly.

I have had the same thing happen.

Keyboard no longer responsive.

I did all the things you did plus more such as going to older version of my Windows/xp that I save with Nortong Ghost.

I re-installed by first removing and deleting the game completely, but the keyboard is still not recognized; even if I start a brand new game

There is another thread in forum reporting same issue.

This is coincident with "Dead Money" add-on being announced.

Clearly, an update was added to the game platform that is "forgetting" to detect USB Keyboards.

In the other thread, a gentleman suggested going back to a PS/2 keyboard.

I don't think this is the right way to "fix" a problem.

Hopefully, steam and/or bethesda fixes this issue soon.