Things I've checked already:
1) drivers are installed correctly on my Win7 box
2) fastboot -i 0x1949 commands are being recognized from the command line
3) I have the same result whether I use a standard USB cable or a fastboot cable
All I want to do here is get it running a stock ROM - no root, no bells and whistles, just get the thing running as it would if it had just came out of the factory box. I've tried various methods described in other threads, but nothing has worked.