ReadFile error in log - SN doesn't work

[IGW]

I have never been able to get my SN working well.

In the long distant past I had a problem with the service that was never really resolved. See this thread:
viewtopic.php?t=2051&highlight=

I recently decided to try again. Uninstalled old driver etc and downloaded new driver. SN and driver worked after installing (demo apps worked). Also the SN works fine on another computer.

After restarting the computer a few days later though the SN doesn't work - the service is not chewing up a full CPU so this is not quite the same issue as I had before. CPU usage is low, but the SN doesn't work including in the demo apps.

Looking in the log file I see a constant stream of:
Unhandled error from ReadFile(): code 0x000006F8.
whenever the SN is plugged in and the driver started.

I have tried the two button press thing.

Any ideas?

Thanks,
Ian