NAS connection issue

I have a Buffalo NAS which backs up all the PC in my house but I have a niggly issue I need to sort out .I can see the NAS ok and I can access it via navigator and also log onto it fine using the admin portal and password .The frustrating thing is when it goes offline to the PC and I have to log on again it asks for the admin and password which I put in and I check the box for remember me , but when I next have a backup say next day after restarting the pc it cannot access drive as it is offline again ,is there a way to keep it online and accessible via the backup routine so that it backs up without intervention .It uses a very useful routine such that when all my PC power down for the night if it doesn't detect the NAS navigator software on a PC for 2 mins it then goes into sleep mode ,would this be affecting it .

 

Map the share as a network drive.
In Explorer hit ALT, Tools, then Map Network Drive
\\nasboxname\share
check reconnet at log on, supply credentials if needed.

 

Do you have a password set for the for the profile that is trying to send the backup to the NAS? Mine would not work if I did not have my profile password protected. Just a thought.