HTC Sync is being really flaky when it comes to recognising my phone. I have USB debugging enabled on the phone, plug it in, then select Sync. Sometimes HTC Sync recognises it, and I can install applications to my phone from my PC, but sometimes it doesn't recognise the phone, I've tried un/reinstal HTC Sync, and rebooted the phone, makes no difference. At the moment I can't get it to recognise the phone at all. How come it works sometimes and not other times?