d-b,
Hi and welcome to the Daniweb forums :).
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Still in HiJackThis, click "Scan", then check(tick) the following, if present:
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Bar = http://red.clientapps.yahoo.com/cus...rch/search.html
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://red.clientapps.yahoo.com/cus...rch/search.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://red.clientapps.yahoo.com/cus...//www.yahoo.com
Now, with all windows closed (including Internet Explorer) except HiJackThis, click "Fix checked".
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After rebooting, rescan with hijackthis and post back a new log. Let me know how everything goes.