You could try showing all field codes (Alt F9) then doing a search and
replace to replace all instances of E:\ with C:\. Then AltF9 again to switch
display of fields back to results then select the whole doc and F9 to update
the fields.
I tried that with no luck. It turns out that the file was opened from a CD
and then had a save as performed. Now when you look at the edit hyperlink box
it says E whereas if I open the original from the CD it does not