Downgrading to directx 9.0c

hi, i was wondering if anyone could tell me how to downgrade my directx10 to directx9.0c? the directx10 came with my com and my graphics card is nvidia geforce 100m series. i need 9.0c because it's causing incompatibility with some of my games and its so annoying i feel like bashing microsoft for not letting me remove it. i already tried downloading directx9.0, which just insisted that it's already installed (?????) and and tried the directx eradicator program and also updated, rolled back my drivers, used the program compatibility wizard, all to no avail. i really, really need directx 9.0c. My OS is windows vista and directx 10 seems to be embedded in it :((((. someone PLEASE PLEASE HELP ME

You can't directly downgrade your DirectX 10 to 9 on your system. For more information on the above issue, you can check out the following link. You can't replace DirectX 10 on Vista, not without downgrading the OS as well. DirectX 9 is essentially incompatible with Vista drivers, so it won't run directly on Vista (and conversely DirectX 10 won't run on XP or earlier for the same reason).