Another great free tool for finding out everything literally about a system is the System Info for Windows tool(SIW) found at http://www.gtopala.com/
That one provides a larger variety of information on programs as well as the hardwares!
As for downloading the 7 RCs you still have time for that if you feel the first download(s) were incomplete or simply bad or deleted by accident from the drive. The end of the availability still hasn't been specified at MS quite yet with the only indication of being extended into July.
To see either of the 32bit or 64bit RCs installed be prepared to reformat the existing Vista primary in order to perform a fresh clean install of 7 since it is still not a finished version while some progress has been seen in the RCs themselves.
The typical installation time runs about 20-25 minutes to reach the desktop with a fresh copy going on over the old 45min. seen for previous versions including Vista. Write down the product key seen when at the download page.
If that fails to work as seen here with the first RC install simply return to the download page and login again to get the next key seen. There are 15 total for the 32bit as well as 15 for the 64bit.