ciao,avvia hijackthis,spunta a sinistra su queste voci:

O2 - BHO: (no name) - {7E853D72-626A-48EC-A868-BA8D5E23E045} - (no file)
O4 - HKLM\..\Policies\Explorer\Run: [5T19I3B27A] C:\WINDOWS\csrs.exe
O9 - Extra button: (no name) - {A2199168-22AC-44A3-BA5F-8A83E693FEBF} - java-script:window.location.href="http://www.cercasulweb.com/itmp3/" (file missing)
O9 - Extra 'Tools' menuitem: Cersa Sul Web - {A2199168-22AC-44A3-BA5F-8A83E693FEBF} - java-script:window.location.href="http://www.cercasulweb.com/itmp3/" (file missing)
O9 - Extra button: ScaricaMP3 - {EF6D6AE3-2625-40D6-A5AB-920DFD2DAF8C} - C:\Documents and Settings\UTENTE\Dati applicazioni\ScaricaMP3[1].exe (file missing)
09 - Extra button: Cersa Sul Web - {F4445FEB-6D20-47CB-9ACF-9D142A7F680A} - C:\WINDOWS\system32\Cersa Sul Web (file missing)
O9 - Extra button: Scaricando MP3 - {810B72CB-566A-409B-B6A3-31F720C16FAE} - C:\WINDOWS\system32\Scaricando MP3 (file missing)
- Extra 'Tools' menuitem: Scaricando MP3 - {16930DCA-0910-4C00-86FF-0C73872D4ABA} - java-script:window.location.href="http://www.scaricandomp3.com/link/" (file missing)
O9 - Extra button: (no name) - {16930DCA-0910-4C00-86FF-0C73872D4ABA} - java-script:window.location.href="http://www.scaricandomp3.com/link/" (file missing)


e clicca sotto su FIX CHECKED.