Calling all experts!!

I am working on a project that needs to do some heavy data manipulation to approx 500,000 records per month. I have created a number of macros that are manually run by a user (a single user whom I have trained) on each worksheet within a workbook. The essential functions for each of the 5 macros are:

1. Find and Replace macro that searches for a corrects incorrect or common mispellings.
2. Location macro that separates out the two-letter State abbreviation from a column and creates a new column for it. This macro also 'Paste Special - Values' into a new column and then deletes the column with the Trim formula.
3. Split Cell macro that trims out specific data contained in one column and divides it into 3 columns.
4. Paste Values macro that does the 'Paste Special - Values' function to the above newly created columns and deletes the columns with the Trim formulas.
5. New Sheets macro that cleans up unused rows and hidden columns.

Note: The reason for the 'Paste Special - Values' functions are that this data is imported into an Access Database following manipulation in Excel.

Now the problem.....I have created these macros on my machine in my home office and copied them onto the target machine at the business where it is to be used. Both machines are relatively new running XP and Office 2003. The target machine is on a local, hardwired network.

While I had unqualified, initial success on the target machine for one monthly cycle....now the macros run unacceptably slow on the target machine. I am able to run all five macros through 7 worksheets on my machine in about 30 minutes...perfectly acceptable considering the amount of data! While I have not done a complete run-through on the target machine....it appears that it would take many hours for one worksheet.

I have:
  • Turned off network connections (and even unplugged the LAN cable) on the target machine - no help
  • Made sure that I have a self-certified digital certificate on the target machine for myself and the user
  • Re-created the macros on the target machine by cutting and pasting the code into new macros

The perplexing issue for me is why is works so flawlessly on my machine, but is slower than a glacier on the target machine.

I have seen the "Screen Updating/Application Calculation" sub that I may try....but I am not overly hopeful!

Any thoughts/advice would be greatly appreciated!!

Thanks!!