Important Files missing

Hello,

my computer is missing important files from the windows folder..

such as Msiexec.exe and that causes alot of havoc sense i NEED that program to install games i do first time setup from Steam ( in this case Dragon Age Origins: Digital Deluxe )

the problem is that when i try to run it.. it freezes my entire taskbar.. however i can stil press buttons and so.. ( no CPU rapid increase )

anyone that can help me out?



( general info about tested things- i made the upgrade first, when i noticed the problem was with the msiexec i did a clean install in C-harddrive, didnt work.. i also tried regcure shit.. didnt made anything.. pure bullshit )