So I got New Vegas just before Christmas, and everything worked fine for a while until the patch came out. After Steam automatically patched the game, it told me my it had updates for my video card drivers, so I decided to install them (ATI Stream SDK.) That's when everything went to s***. New Vegas would hang on startup, just getting to the black screen before the first intro slide. When I check it in the Task Manager, it's using ~50% of my CPU. FO3 would get to the first intro slide before crashing. Since then I've tried everything. I tried every ArchiveInvalidation fix I could find, the dxd9.dll fix, reinstalled several times, starting with no mods, starting with one mod at a time, with the new FOMM and NVSE, with the new FOMM and not NVSE, and without either. I tried einstalling Catalyst Control Center (this was especially enjoyable :pinch:) and actually ended up making it just flat-out not start, and it was then I decided to just take off and nuke the site from orbit. I backed up everything and used my recovery disc. That got FO3 working again, but New Vegas would still hang on startup. I have the latest .NET 3.5 service pack. I am totally out of ideas. My DXDiag is included.