Hi,
has the drive been dropped or removed from a pc before it has been 'stopped'. If so it can lose data. What i mean by 'stopped' is when you plug a flash drive in you hear a bing bong and an icon appears in the task bar. To remove the flash drive one should always right click the flash drive icon to safely remove the device.
One thing you could try is show hidden files or folders. This guide will show you how but i wouldn't leave it this way and as soon as your done return to default settings:
Showing hidden files - Windows Help
As for a good external drive I'm not too sure as I've never owned one but other forum users may be able to help you with this.