I am running Win7 64-bit on a sandy bridge (i7-2700k) with a discrete graphics card (Nvidia) and currently developing a Transcoder which works great with MFX_IMPL_SOFTWARE.
// Session init
m_session.Init( (MFX_IMPL_AUTO_ANY | MFX_IMPL_VIA_ANY),&version);
// Always return software
Yes, i7-2700k (Intel 2nd generation Core processor) does have support for HW accelerated decode and encode.
Make sure you have the most recent Intel graphics driver installed on your system. If you are using Win7 then you have to resort to using DirectX9 which does imply some limitations on systems with multiple graphics devices, such as requiring having monitor physically attached to the Intel graphics device to make sure the device is active.