check your registry run/run once /run services keys.....(type regedit in start>run)and navigate (by clciking the little "plus" signs to..
HKeyLocalMachine\Software\Microsoft\Windows\CurrentVersion\Run\
Look for something like nwc.exe (in the right hand pane)whose path point to the nwc.dll in windows folder.Delete this value or failing that right click the entry and click modify.Then rename it too .txt (rather than.exe).Once you have done that delete or rename to txt , the offending nwc.dl in windows folder too.
me