I'm using SP on a win7 64b machine and all was working fine.
Just today after starting the computer, just a small dialog 'Stream write error' is shown.
No icon is shown, but in the taskmanager a process is running.
I have downloaded the latest version and reinstalled.
But still the same.
It's puzzling because there are no new things on the computer.
Maybe windows updates, I'm not sure about that.
On my other win7 machine it is still working.
Can a change in firewall settings on the corparate network be an issue?