I actually started looking around regarding this issue yesterday when I saw your post here
Missing 'Server SMB 2.xxx Driver' Service?
Sadly I haven't been able to find much in the way of valueable information regarding the problem except the standard;
Launch an elevated command prompt and type
sfc /scannow
and of course the old reliable "pick a restore point prior to the issue first presenting"
either or both, very sound suggestions if you haven't tried them already. Does the event viewer provide any more details specific to the issue and the cascading dependencies server service ->smb2.xxx->smb1.xxx->srvnet?