Start by removing this
sptd.sys 11/23/2010
Go here for the removal tool and use the UNINSTALL button to get rid of it Link Removed (get the correct version for your system's architecture 32 or 64 bit)
If that doesn't seem to help with your issue try removing / uninstalling Avast (at least temporarily). Use control panel, programs and features to uninstall and follow up with the vendor specific proprietary removal tool from here Link Removed
Replace it for the time being with MSE from here Link Removed