When you next get this, make a note of the pid number (in the image, pid:4656), now go to windows Task Manager and see what process matches the pid:number.
These are my comments if recommending ST, Resident scanner (if you use this don't install the toolbar or crawler or the anti-virus module).
Do you have the ST toolbar or crawler enabled, because for a long time crawler was considered adware ?
So it may be the toolbar or crawler that it is objecting to and since it is an Adware generic detection signature that could be it.