I am by no means an authority in this, but your request for assistance does raise some questions. For example, based on your equipment, are you attempting to build an HTPC using Win 7RC? If so, I would suggest not to do that ... at least not yet.
The best way to begin, IMHO, is to keep everything as simple as possible. Do a clean install to the SATA HDD using the SATA ODD, with your BIOS set to boot first from the ODD. Use just 1G or 2G of memory to start (although I did manage to install using 8G when I forgot to remove the extra). Forget about the IDE or PATA stuff for now. Make the installation as simple as possible and get it up and running.
Then, you can start adding other components, one at a time, until your reach the point you want to be at. Remember, this is the RC, but it is still a beta. You might even try the 32-bit RC, just to see if it makes a difference. It probably won't, but this is all testing now anyway.
Good luck. Please let us know how the installation is going, and what else you learned from the process.