hmmm. Sometimes there's files missing or something got corrupt in the process. It happened to me before. Make sure you have the system bit rate correct, X86 or X64.
You're gona have to reinstall. If it still turns out bad I would suggest on downloading W7RC again.
Just do the same thing you did to install it in the first place; stick the disk in, wait for your computer to ask you "do you want to boot from the DVD/CD"? and press yes. It will lead you on from there. Make sense?