I can find nothing particularly nasty in your HJT log, that would account for your problem.
However, you should have HJT fix the following.
You might want to copy and paste these instructions into a notepad file. Then you can have the file open in safe mode, so you can follow the instructions easier.
Boot into safe mode. See how HERE.
http://www.bleepingcomputer.com/forums/tutorial61.html
Turn off system restore.(XP/ME only) See how HERE.
http://www.bleepingcomputer.com/forums/tutorial56.html
In Windows Explorer, turn on "Show all files and folders, including hidden and system". See how HERE.
http://www.bleepingcomputer.com/forums/tutorial62.html
Run HJT with no other programmes open(except notepad).Click the scan button. Have HJT fix the following, by placing a tick in the little box next to(if there).
O4 - HKLM\..\Run: [UpdReg] C:\WINDOWS\UpdReg.EXE
O9 - Extra button: ComcastHSI - {669B269B-0D4E-41FB-A3D8-FD67CA94F646} -
http://www.comcast.net/ (file missing)
O9 - Extra button: Support - {8828075D-D097-4055-AA02-2DBFA9D85E8A} -
http://www.comcastsupport.com/ (file missing)
O9 - Extra button: Help - {97809617-3937-4F84-B335-9BB05EF1A8D4} -
http://online.comcast.net/help/ (file missing)
Fix all 016-DPF entries.
O18 - Protocol: msnim - {828030A1-22C1-4009-854F-8E305202313F} - "C:\PROGRA~1\MSNMES~1\msgrapp.dll" (file missing)
Click on the fix checked button.
Close HJT.
Reboot into normal mode and turn system restore back on.
Just to be on the safe side. Go
HERE and follow the instructions.
Let us know how you get on.
Regards Howard
