I would think that system restore would help in this instance. System Restore takes your system back to an earlier time (you pick the day on a calendar you want to go back to. You don't lose any emails or documents. Your system files are just restored to the day you choose. In other words, if you restore your system back to a date before your Service Pack 2 installation, you should get all your old system files back)
From Microsoft:
To access the System Restore Wizard, click Start, and then click Help and Support. Click Performance and Maintenance, click Using System Restore to undo changes, and then click Run the System Restore Wizard.
From the Welcome to System Restore screen of the System Restore Wizard select Restore my computer to an earlier time. Then select the date when the restore point was created from the calendar in the Select a Restore Point screen. All of the restore points that were created on the selected date are listed by name in the list box to the right of the calendar.
Choose a restore point (restore date) that is right before you installed service pack 2. The restore point you want itself probably says something about service pack 2. That's the restore point you want, because what that means is that it will restore your system to exactly the way it was right before service pack 2 was installed. Again, no emails or documents will be lost when restoring. However, any program you've installed after the restore point/date you choose to go back to will have to be reinstalled if you want to use it.