Totally fresh install from steam, got all the latest drivers for my kit, no mods even downloaded, i can boot and create character, get a couple of seconds of gameplay (high framerate & responsive to inputs) then CTD.

maybe my google-fu is weak, but hours of searching the net have turned up no fixes. weirdly enough (or maybe not), the same happens on fallout 3, but dosent even get past the intro movie, and new vegas crashes immediately after the intro movie.

Either inadequate hardware, or UAC issues...... Running Vista, or Win7? Steam installed in program files?

Not UAC issues, its installed to C:\Program files (x86)\Steam\steamapps\common. Running 7 ultimate 64bit. I can confidently say that it is not inadequate hardware. I'm thinking it's the opposite problem I have here.

Try just moving it out of Program Files, that might help.

Or disabling UAC for the Steam folder, and all subfolders.......

Do you have a sound card? If you do, which one?

UAC is already disabled, almost the first thing i did when i got the computer. Got an Asus xonar DX. I'll try moving it, putting it into C:\games

update: didnt work. now when i hit play in the launcher, screen goes black for an instant then nothing appears to have changed, hit it a second time and it loads then CTDs after a few seconds of gameplay.

erm, are you running any of the asus apps in the background while attempting to play? Oblivion REALLY doesn't like them..... (smart doctor, and one other one that I just can't remember the name.)

asus audio centre is running.

Asus Xonar DX.

Make sure to disable GX mode. Oblivion really doesn't like it.

Shouldn't affect Fallout 3/NV so badly though

Well done Romphaia. All three now work perfectly. I can barely believe that a tiny option, with a button about half the size of my fingernail, could cause this. It doesn't even make a difference to the sound.

Thanks for the help.