Reboot into safe mode following the instructions here & Close all (browser) windows & rescan with hijackthis. When the scan is finished place a check in the box to the left of the following entries & click 'fix checked':
R1 - HKCU\Software\Microsoft\Internet Explorer,Search = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer,SearchURL = http://bestsearch.name/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer,Search = http://bestsearch.name/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer,SearchURL = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://bestsearch.name/search.html
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = http://bestsearch.name/index.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://bestsearch.name/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://bestsearch.name/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://bestsearch.name/search.html
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://bestsearch.name/index.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Search,CustomizeSearch = http://bestsearch.name/search.html
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant = http://bestsearch.name/search.html
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch = http://bestsearch.name/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
O4 - HKLM\..\Run: [winupd] C:\WINDOWS\System32\winupd.exe
O16 - DPF: {11010101-1001-1111-1000-110112345678} - ms-its:mhtml:file://c:\nosuch.mht! http://69.50.188.194/winsearchie32....nsearchie32.exe
-Adult Content Dialer
Delete the following manually:
C:\WINDOWS\System32\winupd.exe-file
Reboot normally after doing the above then post a fresh log please.