Repaired Excel file charts flash up briefly then disappear..

I created a file (file1) containing plots and regressions and saved it. I
reopened it and resaved it as file2 and then inserted new data. It seemed OK
but some of the plots were now mislabelled so I set about relabelling them,
saving regularly. One of the plots locked up on a text box - selecting the
plot always highlighted the text box and nothing else could be changed. I
tried to save the file and it crashed. Trying to reopen it, I saw my plots on
the screen behind a box telling me Excel couldn't open the file and did I
want to send an error report. Whatever I did next, the plots disappeared and
a "recovered" file appeared with no plots and no formatting. The same thing
happens if I try to open file1. My plots are in there somewhere - how can I
recover them?