In Windows XP everytime you open My Computer to browse folders XP automatically searches for network files and printers. This causes a delay in displaying your icons. You probably see the "default" windows icon and as you scroll it changes to the correct icon. This is how to stop that...

1. Open My Computer
2. Click on the Tools menu and select Folder Options...
3. Under Folder Options select the view tab.
4. Uncheck the very first box that reads "Automatically search for network folders and printers".
5. Click "Apply" or "OK"

You should see a dramatic increase in speed when Windows displays your icons.