OK, here is the saga up until now.

I have tried and failed four times to clone the system drive and boot a new bigger drive using the Easeus software. Each cloning took about 8 hours for a 500GB drive <sigh>. I then purchased the Easeus Backup Workstation software and tried another cloning with it, another 8 hours and another failure to boot. Then I used same software to do a Backup rather than a Clone. At that point I felt comfortable using the nuclear option that Roman recommended which was to use the Partition software to resize the system drive in place on the original drive. First I shrunk the Vista drive (D) of most of its free space, a 4 hour operation, then I allocated the 100gb to the Windows 7 drive (C), a 6 hour operation. That just finished...AND IT WORKED!!!

Now I have removed the somewhat healthy resized system drive and I am using the Easeus Recovery program to attempt to build a new system drive on a 2TB platform. It says it will take 7 hours for that. If it works I will have a new system drive with plenty of space, and I'll set the 500gb drive in the safe for any future potential recovery.