i also have this issue but windows is not involved.
I have a NAS directly plugged into my WDTV Hub.
Hub connected router via ethernet
SMP connected to router via wifi. mymedia is connected tot he hub and NAS only.
in order to make my experience with the SMP as painless as possible I walk in the room and pull the power cord and plug back in and let it rescan files. but i have to wait for it to scan 6TB of drives. This makes the experience painless 90% of the time
If i do not do this and just turn the SMP on, i navigate to what i want and click on it, only to receive and error, content doesnt exist.
then i have to get up and go pull the power cord anyways. this happens 90% of the time if i dont pull off the start.
The other 10% in both circumstances even the power cord pull doesnt solve the issue. i sometime have to go in and delete mymedia shares and add them back.
This losing connection but keeping caches garbage is a bane of existance.
I have ordered Vmedia for July and it will replace my Bell Fibe and my WDTVs and I will be done with the terrible network issues of SMP and the non-existant support for the hub [even though they are the exact same device except for the built in HDD]