You can also use a Debug.Print statement
Debug.Print "Loop 1 Complete!"
After each loop to see how far you get before it hangs.

Also, if this is a workbook you've been extensively working on and doing a lot of VBA editing over a long period of time, keep in mind that VBA is somewhat notorious for not properly cleaning up after itself. This can lead to very strange behavior at run time. I HIGHLY recommend installing Rob Bovey's free code cleaner and cleaning your project to clear out any 'garbage'.

http://www.appspro.com/Utilities/CodeCleaner.htm