My Personal.xls is in

C:\Documents and Settings\David\Application Data\Microsoft\Excel\XLSTART

You would need to replace "David" with your username

You might also look in the adjacent directories like AltStart.

Also, in Excel look at Tools/Options then "General" Tab and look in the paths
shown in

Default file location:
and
At startup, open  all files in:

Also on the "Save" tab look at

AutoRecover save location: