XP automatically searches your network for any network shares (Printers and Files). While it's looking for this information you're sitting there waiting for your stuff to be displayed. If you'd like to speed this up then here's your instructions.
Open My Computer
Click Tools --> Folder Options
Select the View Tab
The first box says "Automatically search for network folders and printers" Uncheck the box next to it.
Click "Apply" or "OK"
This will boost your loading of drives when you open my computer.