aboshakeeb - 7:25 pm on Sep 25, 2013 (gmt 0)
I went through this 2 year ago , the symptoms is little different but same direct annoying hits .
The puzzle solved after a year . it was a Trojan : TROJ_OBVOD.TA
more info here : [about-threats.trendmicro.com...]
the Trojan is still functioning and some machines is still infected until now .
Check if your Site is listed above .