I'm Greg, an installation specialist and 8 year Windows MVP, here to help you.
Everything possible is here to start Windows: http://answers.microsoft.com/en-us/windows/wiki...
If nothing works then there is one last resort. You can use a bootable Partition Manager like Easeus to boot and shrink C by about 50 gb, then boot Windows media to Clean Install to the shrink space. This may create a Dual Boot menu that actually starts the old install.
If so then I help you remove the rescue install and recover the space.
If not you can set up the new install copying the files over from the old one, when ready I'll help you remove the old install and recover its space.
Otherwise you can wipe the hard drive and do this gold standard Clean Install which should get you past all difficulties as it has hundreds of thousands of others who have followed the steps in this link and never come back to report another problem: http://answers.microsoft.com/en-us/windows/wiki...
I hope this helps. Feel free to ask back any questions and let us know how it goes. I will keep working with you until it's resolved.