I had a problem similar in there was something that was taking window focus away from my main window and 100 different programs all found nothing.
Until I ran an older program I used to use quite often until Adaware and Spybot became the standard. It is called Swatit, it is a trojan/bot finder and believe it or not, it did find what was the problem, an exe file I knew nothing about in my root dir, once I got rid of it I have had no problems. You might want to give it a run in safe mode and see if it can help, it is freeware and can be downloaded at:
http://lockdowncorp.com/bots/downloadswatit.html
You have to enter your e-mail and they send you a download link, but what I did was hop on
http://10minutemail.com/10MinuteMail/index.html get a free 10 minute email addy and enter that to get your swat it dl link, then just close the 10 minute mail addy and don't worry about spam. Also something else you can try is Webroot's Spy Sweeper, I personally have never used it, but have heard many good things about it's detection and deletion. Also I assume you have an AV program from seeing the Symantec/Norton entries in your log postings but check out AVG and or Avast and see if either of them pick anything up and check out Trend Micro's free online AV scan just as a double check to see if your system is clean.