Make sure that Internet Explorer is not running, run HJT again, and have it fix:
O4 - HKLM\..\Run: [windows] iexplore.exe
O4 - HKLM\..\RunServices: [windows] iexplore.exe
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
Although your log currently shows no signs of malicious infections, if the IE "Run" entries in HijackThis automagically reappear at some point, I'd start suspecting foul play.