Smiley Central is well known SPYWARE.
My advice would be to remove it
permanently.
Spyware causes your system to slow down as well as sending personal surfing information to spam marketeers.
To make sure everything is running fine run both anti virus and anti spyware apps in normal AND safe modes. (make sure that they are updated first !

) (
AVG is good and free AV)
(A couple of good removal tools are
Spybot and
Adaware)
ALso an on line virus and spyware scanner is
Trend Housecall
Just a note; actively running two AV's on one machine can cause problems.