Clarity over Requirements for Refreshing Local Files

Hi all, 

Looking for some answers on connecting to local or network files from Power BI Service.  Two part question really:

1. Is there a difference in setting up local files (ie. to desktop or basic folder on my device) vs. setting up to a network location?  I noticed I can access my company's network files via a weblink in File Explorer so was wondering if there is a way to set up the refresh so that the device does not have to be 'on'.
2. If the answer to the above is that the local file connection and network file connection are the same, what are the specific conditions required for refresh to succeed?  For example:
   
   1. The computer has to be on?
   2. The computer has to be on but not in sleep?
   3. The computer has to be on, not in sleep but the screen can be locked?
   4. The computer has to be on, not in sleep and the screen not locked?

I noticed that my refresh failed this morning despite my computer being on, but it was probably in sleep mode.

Thanks in advance!

Kirsty