ReadyNAS 212 (FW 6.6.1) Host not visible, shares not visible and can't start SMB

I'm having a very odd combination of issues with my ReadyNAS 212 which all occurred together and therefore I'm pretty sure are related.  The issues are:

1. The NAS hostname is not visible on my (windows workgroup) LAN.  I can ping the IP address directly, and I have checked that the hostname is listed in the DHCP table on the router (which is providing the DHCP server).  However, the hostname is not accesible from any other host on the network (e.g. ping NAShostname gives "Ping request could not find host massaya."  To put this another way, arp -a lists the IP address, but net view doesn't list the host name.  Note that all other hosts on the network are listed in both.
2. When browsing the NAS using the admin page, I cannot see any of the shares that exist on the NAS except for the Home folders (which contain only two subfolders, one for admin and one for the only user account created on the system).  These are empty.  However, I know the rest of the data is there somewhere, because the disk storage shows it half the storage being used.
3. In investigating these problems I noticed that the SMB service was off.  I tried to turn it on but it doesn't turn on - no error messages, no log messages, nothing.  Other services seem to be working (e.g. FTP, HTTP).

To be honest, I'm not a hundred percent sure how the problem started.  Here are the steps I think led to the issues:

• While renaming one of the shares, the admin console started taking a long time to respond, then came back with a error page along the lines of "cannot accces the host".  At this time, I found I couldn't access the shares anymore - I think this is when the hostname stopped being accessible.
• As part of trying to fix this based on info from other posts in this forum, I figured it was a problem with space running out on the OS partition - my log files showed the "Volume: Less than 5% of volume media's capacity is free." warnings.  To try to resolve, I deleted the logs, disabled anti-virus and uninstalled Plex (which was the only app on the NAS at the time, although it was not running).  (Unfortunately, I neglected to save those logs before deleting).
• At this point I noticed that the host name was not accessible.  I eliminated any issues with the router, then rebooted the router and the NAS to try to resolve.  I then did an OS reboot on the NAS.

Only other point worth mentioning is that ReadyCloud was enabled - I don't think it contributed but it's the only other which was turned on at the time.

I'm now at my wits end trying to solve this - I'm not a networks guy, and this is just a home network so I'm struggling with what to look at next.  Any suggestions for solutions or avenues of investigation would be much appreciated.