Scan with hijackthis and tick the boxes next to all the following entries, then close all browser and explorer windows, and hit the "Fix checked" button.
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = about:blank
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://www.isearch.com/index.php?ref=none
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = about:blank
R3 - URLSearchHook: (no name) - {1C78AB3F-A857-482e-80C0-3A1E5238A565} - (no file)
F2 - REG:system.ini: Shell=Explorer.exe winsock.scr
O4 - HKLM\..\Run: [dxset.exe] C:\WINDOWS\dxsetu.exe
O4 - HKLM\..\Run: [C:\WINDOWS\System32\ope3C4.exe ] C:\WINDOWS\System32\ope3C4.exe
O4 - HKCU\..\Run: [SpywareKilla] C:\PROGRA~1\SPYWAR~1\SpywareKilla.exe /s
O8 - Extra context menu item: &iSearch The Web - res://C:\WINDOWS\System32\toolbar.dll/SEARCH.HTML
O9 - Extra button: Related - {c95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\WINDOWS\web\related.htm
O9 - Extra 'Tools' menuitem: Show &Related Links - {c95fe080-8f5d-11d2-a20b-00aa003c157a} - C:\WINDOWS\web\related.htm
O16 - DPF: {15AD4789-CDB4-47E1-A9DA-992EE8E6BAD6} - http://static.windupdates.com/cab/ClickYesToContinue/ie/bridge-c11.cab
O23 - Service: WLTRYSVC - Unknown - C:\WINDOWS\System32\wltrysvc.exe C:\WINDOWS\System32\bcmwltry.exe (file missing)
Download the Pocket KillBox
Unzip the file to your desktop.
Run Pocket Killbox and paste the full file path of each of the below files in the box and click on Standard File Kill and End Explorer Shell While Killing File. Click on the button with the red circle and an X in the middle after you enter each file (see the files below).
C:\WINDOWS\System32\svcnet.exe
C:\WINDOWS\dxsetu.exe
c:\windows\winsock.scr
c:\windows\dxsetu.exe
c:\windows\system32\winlog.com
c:\windows\system32\dxwinex.exe
C:\WINDOWS\System32\ope3C4.exe
Reboot afterwards if the files are successfully deleted.
If all files are not deleted, do not reboot yet. Run Pocket Killbox again and paste the full file path in the box and click on Delete on Reboot. Next click on the button with the red circle and an X in the middle. You will get a message saying "File with be deleted on next reboot, Process and Reboot now?" Click "Yes" to reboot only after the last file you enter.
Delete the Spykilla folder and get Adaware SE and Spybot S&D instead.