Lisa:
I have good news to report. I have now installed CCSv5.5 on both my Windows 7 desktop and my Windows 8 laptop. In both cases I did run the setup as Administrator. That was the key, apparently, in Windows 7, and I didn't bother to check if it wasn't necessary in Windows 8. After installing the license files I was able to run the example blink-the-led code that talks to an MSP-FET430U100C, from both machines.
Thanks for the help.
Laurence