Soselia :
i uninstalled speedfan and haven't encountered problem while doing anything else ( including using other sensor software ) and i have no real need for speed fan. so this is not hardware related? any way to check that?
With many people having the exact same problem (i.e. http://www.bugtrack.almico.com/view.php?id=2007) I would doubt there's an issue with your hardware, most likely just a driver issue. If you don't need it I would just get rid of it...
Or you could create a a batch file to launch it with the /NOSCSISCAN command rather than having to open command prompt and launching it through there every time