Values of a Regsitry Key Automatically Restored?

Our software product creates a registry key

HKEY_CURRENT_USER\Software\Company Name\Product Name\Items\ItemA\Info1

Info1 is a subkey and it has some values.

When our software shuts down, we will

1. delete the Info1 subkey to completely clean up.
2. recreate the Info1 subkey.
3. put some values there to save the states.

Everything works fine on all machines except one. This machine has Windows Server 2003 R2 Standard Edition Service Park 1. Some other machines also have the same OS. But the problem only happens on this machine. After step 2 and before step 3 above, some values are automatically restored. To isolate the problem, I've written a small program to do exactly the same thing. My small program does step 1, 2 and 3. In between the steps, I pop up a message box to pause the execution. After step 1 and before step 2, I verify with the Registry Editor that the Info1 subkey is gone. After step 2 and before step 3, I verify with the Registry Editor that the Info1 subkey is created without any values. But on that particular machine, some values are automatically restored right after I recreate the Info1 subkey. The strange thing is that those values are NOT the last saved values and they are the same every time.

Our software uses InstallShield and MSI.

Does anyone have any idea what is going on? Is this an MSI feature? Is this an OS feature?

Thanks.