I have a workbook last saved from Excel 2003 in November 2007, in which I was
using the Solver. I didn't use the Save Model option, because Solver always
remembers its parameters. Now however, opening the workbook again in Excel
2003, all of the parameters (target cell, cells to change and constraints)
have disappeared. Several other odd things have also happened:

1. The workbook has acquired lots of named ranges and variables like
solver_lhs1 etc. that definitely weren't there before; some of these seem to
contain the missing Solver parameters, but there's no obvious way of loading
them back into Solver.

2. If I set the parameters up again from scratch the optimisation seems to
run OK the first time, but if I then try to run it again some parameters are
corrupted, e.g. the cells to change have been defined using a named range
that does not correspond to the range I entered.

3. After running it once the Target Cell is also changed to use the name
solver_opt, which does not exist in the Define Name dialogue, although the
correct cell is highlighted while the Solver is open (so it's behaving like a
'hidden' name).

Is the workbook corrupted, and if so, do I need to copy all the data to a
new workbook and set up the Solver parameters from scratch again?

Could this have been caused by an Excel patch that I've installed since I
last opened this workbook? The workbook timestamp is still November 2007, so
it doesn't appear to have been touched since then, when it was working fine.

Richard