Epson 3170 Photo Scanner, Problem scanning 35mm color negative

I have an Epson 3170 scanner. I have scanned many color negatives in the
past without difficulty but now the scanner or software seems to think the
35mm negatives are only 32.2mm wide. I get part of the fist negative in the
first thumbnail. The second thumbnail has the rest of the first plus some of
the second negative and so on. I have tried unistalling the drivers and
reinstalling both from my disc and from the latest update. The problem
persists. It scans and finds slides and multiple prints ok.
I tried the demo of VueScan and after I setup the frames it works ok.
Playing with VueScan leads me to think it is a software or driver problem.
Somewhere there is a setup file that has the wrong dimensions for 35mm Color
Negative film. Uninstalling the Epson Scanner software may not clean out
everything so the problem persists.

I sure hope someone can advise me on a solution.