I often see the notification balloon popping up from system tray to tell me that my network drives could not reconnect. I typically see this after I've first turned on my computer or after I've booted from Hibernation.
When I open Computer, I can see my network drives, but they are shown with a red cross indicating that there is indeed a problem with the connection to them. Applications which rely on data from these network drives cannot obtain their data, and fail in their own ways. The particularly annoying aspect of this is that there absolutely no problem with the network connection to these drives. Simply double clicking on the drives will open them up and restore the connection. All applications will function correctly thereafter... until the next time I boot up the machine.
Below is a workaround you can use to ensure your remote drives are available for use when you turn on your PC. For my environment, I'm running Windows 7 64-bit and have a Synology DS411J which is a NAS drive. But really, this should work for connecting any remote network drive.