Excel 2007 on XP Pro up-to-date

After working fine for over a year, Excel 2007 now freezes when I attempt to close it.
Excel does close the worksheet(s) but it hangs in memory and on the screen.

When I click the Red "X" a second time to close, I get Visual Basic error 400.

In addition, I am also getting error messages about Add-ins causing a "major error" and a
question as to whether I want to disable them. The particular Add-in named as causing the
problem changes each crash: i.e, PUP7, Synkronizer, and two to three others unnamed here.

I did go through and inactivated all of them and the problem seemed to go away but came
back with vengeance.

In prior versions, I recalled the need to delete a certain file used by Excel during startup.

In 2007, I am not sure what to do.

TIA EagleOne