Sounds like hardware issues, you will need to physically take out the hardware(e.g. sound cards, tv tuner, etc.) just start system with only the bare motherboard, video, ram and hard drive.
Make sure you have the latest drivers, but not beta drivers.
Microsoft does have an official Windows 7 Support Forum located here http://tinyurl.com/9fhdl5
. It is supported by product specialists as well as engineers and support teams. You may want to check the threads available there for additional assitance and support.
Microsoft Windows Client Team