Games not running on a core 2 quad

pllllllllllls help
no game is running on my pc
the error comes as (Suppose the game is Batman)
"BmStartApp.exe is not a valid windows application"

But the miracle is "Dark Sector Runs Very Finely On My PC"

my pc is
Core 2 Quad
Nvidia 9400gt
g41 motherboard

plsssssssssssssssssssssssssssssssssssss ssssssssss

Where are these games from? Have you tried to re-install the games?

[Moderator]

Do other programs run? Do most .exe files run properly? Did this just start? Did those games ever run? Is it most games, all games, one game? You need to provide more information.

Are you talking about a game that was purchased?

yes i had purchased the games

yes the were running on my pc earlier

after dark sector,today another game ran on my pc -FALLOUT 3-
(is ther any releation between these games Requirements)

but when i ran Mark Ekos getting Up The Same error came