Hey Lola. XP needs updating pretty bad (Windows Update), and you have a few entries to fix. I do the fixing, then you do the updating, deal ?!!
Have ONLY HijackThis! running, and check to fix the following entries (then click on "Fix checked") :
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://red.clientapps.yahoo.com/customize/ie/defaults/sp/sbcydsl/*http://www.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://red.clientapps.yahoo.com/customize/ie/defaults/su/sbcydsl/*http://www.yahoo.com
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Bar = http://red.clientapps.yahoo.com/customize/ie/defaults/sb/sbcydsl/*http://www.yahoo.com/search/ie.html
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://red.clientapps.yahoo.com/customize/ie/defaults/sp/sbcydsl/*http://www.yahoo.com
R1 - HKCU\Software\Microsoft\Internet Explorer\SearchURL,(Default) = http://red.clientapps.yahoo.com/customize/ie/defaults/su/sbcydsl/*http://www.yahoo.com
F2 - REG:system.ini: UserInit=C:\WINDOWS\System32\Userinit.exe
O2 - BHO: (no name) - SOFTWARE - (no file)
O9 - Extra button: Coches - {AF0828BC-CB46-4C8D-95B6-8A7C4988F9FF} - c:\nge-pillamusica\entrar.html (file missing)
O9 - Extra button: (no name) - {CD67F990-D8E9-11d2-98FE-00C0F0318AFE} - (no file)
O9 - Extra button: Internet Cleaner - {45819E58-6E84-4A5D-BD65-A706981E5BE8} - C:\Program Files\Internet Cleaner\ICleaner.exe (file missing) (HKCU)
O9 - Extra 'Tools' menuitem: Internet Cleaner - {45819E58-6E84-4A5D-BD65-A706981E5BE8} - C:\Program Files\Internet Cleaner\ICleaner.exe (file missing) (HKCU)
O15 - Trusted Zone: *.napster.com
Fix these two if you haven't set those restrictions :
O6 - HKCU\Software\Policies\Microsoft\Internet Explorer\Control Panel present
O6 - HKLM\Software\Policies\Microsoft\Internet Explorer\Control Panel present
Fix this next one if you or your ISP haven't set this :
R1 - HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings,ProxyOverride = 127.0.0.1
Finally, fix this one if you've removed "Internet Cleaner" as I suspect :
O4 - HKCU\..\Run: [Internet Cleaner] C:\Program Files\Internet Cleaner\ICleaner.exe -c
That's it. Reboot your machine. Scan with HijackThis! again, and post a fresh log. Good luck !