A Base System Device can range from a card reader to a chipset device on your motherboard.

In some cases, after re-installing Windows OR after attaching a new component, you may under Device Manager > Other devices, find an entry by the name of Base System Device - and these may show as Not Installed.

This could occur if the drivers for the hardware on your computer is not installed correctly.

To rectify this situation, you should try and locate the drivers for it. It could be on the software CD that came with the computer or you could visit the computer manufacturers website.

Anyone wants to throw more light on this, please do so!