You deleted the files and they're still being opened?
You may want to search for book*.xls and delete all of them (in case you missed
a few).
But excel will create a new workbook each time you open excel.
But it's called book1 (no .xls in the title bar).
If that's what you see, it's normal.
If you still see book1.xls, then use windows search once again.
====
You can tell excel to stop creating that new workbook by creating a new shortcut
(on your desktop??).
Just point at your copy of excel.exe and append " /e" to the end:
"C:\myfolderthatholds\excel.exe" /e
You'll see a grey window when you open excel.
I renamed and deleted the book.xls file in the XLStart folder and it still
opens both files.