It seems that it might be usbser.sys
1. Is it likely to be the Arduino driver or Windows If Arduino driver, am I using the most recent one?
2. If Windows is it likely to be because Im using Windows 8? Ill try my laptop - it also runs Windows 8, to see if it behaves the same.
3. Could it be exacerbated by the fact the Arduino is busy spitting out characters to the port?
Should I upload blink or comment out all the Serial.Print statements?
4. I have other USB things plugged in eg a Seagate drive I use for backups - is it worth pulling them out?
...was it just the INF file that wasn't signed??
- Not sending any characters from the Arduino ( ie even the blink program which doesn't use Serial at all) doesn't make the problem go away.
Do any other users get this behaviour or am I the only one
You've all been very helpful, but if the fault lies in Microsoft code there may not be much that can be done?