OKOK folks, here's more.
Got the hidden file down to 36.7 gig with 20.5 free. Not good enough. turned off VISTA automatic backup (!). Still no joy.
More research. According to WINDIRSTAT blog on hidden files, this is a problem with the Lenovo computers
To keep it simple: Lenovo bundles a backup (Rescue and Recovery) program under Lenovo Care. VERY special. So I opened it and found I had not configured the backup process (didn't know) after computer purchase. It defaults to backing up to the local C: drive without notification or space limits...eek...and herein lies the problem.
Soooo...open Rescue and Recovery and go to Back Up Your Hard Drive. what I did was this:
I cancelled automatic backup here also.
I went to Manage your settings and eliminated anything automatic (i.e. scheduling)here also just in case.
I was able here also to limit the cache for backups to 2 GB in my case. Check the box.
I changed the backup drive from C: drive to my external USB backup harddrive.
Guess what?!!!!!! Doing that erased all the former backups from my C: drive. Bye Bye hidden file (in about 3 seconds). Hello 57 GB of free space.
Then I would suggest running a backup to the external drive just for safety.
Beware all Lenovo owners: take care of this one.
BTW, an earlier post suggested malware...:-) I think I found it!!!
Best Regards to all for the help and hope this helps someone else...it sure freaked me out.