Depending on how you've upgraded versions of excel, you may have multiple
XLStart folders.

To find the "current" XLStart folder, I'd do this:

Start excel
hit alt-f11 (to get to the VBE)
hit ctrl-g  (to see the immediate window)
type this and hit enter:
?application.StartupPath

Then make a note of that folder.

Now close excel

windows start button|search
look for XLStart
Go into each one consolidate what you want to keep into that "current" folder.
You may want to just move those files in the various XLStart folders to a nice
safe location.

Now back to excel and create a workbook template and save it as book.xlt (as a
template) in that current XLStart folder.

Now when you click the New icon on the standard toolbar, you'll get a new
workbook based on this template.