Yesterday i was downloading and uploading music and pictures from and to my phone. When i tried to "safely remove" the phone the error message was this device cannot be removed because it is still being used (something along those lines) now there was nothing using it (but this message does come up sometimes) so i decided to pull the USB out. And my computer didn't restart. But when i placed the USB cable back in my computer didn't recognise the device. After a restart the computer recognised it, and again restart when i pulled the USB out.