Weird idea but have you tried swapping the units around ?
I'm pretty sure from memory that solved the same problem I had with them (although I could be remembering wrong and talking bollocks of course ) !!
I have tried a number of cables and different ports on my router (I have also switched the 2 units over) and still have the same problem.
Unlikely but they could of course have gone tits up since you last used them
Mine are running without any software on the pc's and devices including through a four port switch. Have never used the software
