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\Main,Default_Page_URL = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\Search,SearchAssistant = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\Search,CustomizeSearch = about:blank
R3 - URLSearchHook: (no name) - {00D6A7E7-4A97-456f-848A-3B75BF7554D7} - (no file)
Get rid of these if you do not use AIM or AOL
*
O1 - Hosts: 217.116.231.7 aimtoday.aol.com
O1 - Hosts: 217.116.231.7 aimtoday.aol.com
O1 - Hosts: 217.116.231.7 aimtoday.aol.com *
O4 - HKCU\..\Run: [System Update] C:\WINDOWS\System\taskmon.exe
O19 - User stylesheet: (file missing)
Reboot into safe mode following the instructions here & navigate to & delete
C:\WINDOWS\System\taskmon.exe< file. Do not delete the legitimate file which resides in C\Windows
Reboot normally after doing the above then post a fresh log plz.