Ho eseguito le classiche scansioni che proponete ai vari utenti del forum, premetto che pc è vecchio, nonostante tutto cerco di ringiovanirlo un pò =)

Grazie per l'aiuto, avete una pazienza e bontà infinita =)

Logfile of Trend Micro HijackThis v2.0.5
Scan saved at 20.23.49, on 29/12/2013
Platform: Windows XP SP2 (WinNT 5.01.2600)
MSIE: Internet Explorer v7.00 (7.00.5730.0011)

FIREFOX: 26.0 (it)
Boot mode: Normal

Running processes:
C:\WINDOWS\System32\smss.exe
C:\WINDOWS\system32\winlogon.exe
C:\WINDOWS\system32\services.exe
C:\WINDOWS\system32\lsass.exe
C:\WINDOWS\system32\svchost.exe
C:\WINDOWS\System32\svchost.exe
C:\WINDOWS\Explorer.EXE
C:\Documents and Settings\All Users\Dati applicazioni\WPM\wprotectmanager.exe
C:\WINDOWS\system32\brsvc01a.exe
C:\WINDOWS\system32\spoolsv.exe
C:\WINDOWS\system32\brss01a.exe
C:\WINDOWS\system32\igfxtray.exe
C:\WINDOWS\system32\hkcmd.exe
C:\Programmi\ESET\ESET NOD32 Antivirus\egui.exe
C:\Programmi\File comuni\Java\Java Update\jusched.exe
C:\WINDOWS\system32\ctfmon.exe
C:\Programmi\ESET\ESET NOD32 Antivirus\ekrn.exe
C:\Programmi\Java\jre7\bin\jqs.exe
C:\Programmi\File comuni\Nero\Nero BackItUp 4\NBService.exe
C:\WINDOWS\system32\HPZipm12.exe
C:\WINDOWS\system32\svchost.exe
C:\Programmi\Chiavetta Internet MDC655\UIMain.exe
C:\Programmi\Google\Chrome\Application\chrome.exe
C:\Programmi\Google\Chrome\Application\chrome.exe
C:\Programmi\Google\Chrome\Application\chrome.exe
C:\Programmi\Google\Chrome\Application\chrome.exe
C:\WINDOWS\system32\wuauclt.exe
C:\Documents and Settings\Emanuele\Documenti\Downloads\HijackThis.exe

R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = about:blank
R1 - HKCU\Software\Microsoft\Internet Explorer\Main,Search Page = http://go.microsoft.com/fwlink/?LinkId=54896
R0 - HKCU\Software\Microsoft\Internet Explorer\Main,Start Page = about:blank
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Page_URL = about:blank
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Default_Search_URL = http://www.aartemis.com/web/?type=ds&ts=1388341410&from=cor&uid=MAXTORXSTM380211AS_6PS2MNKFXXXX6PS2MNKF&q={searchTerms}
R1 - HKLM\Software\Microsoft\Internet Explorer\Main,Search Page = http://www.aartemis.com/web/?type=ds&ts=1388341410&from=cor&uid=MAXTORXSTM380211AS_6PS2MNKFXXXX6PS2MNKF&q={searchTerms}
R0 - HKLM\Software\Microsoft\Internet Explorer\Main,Start Page = about:blank
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,SearchAssistant =
R0 - HKLM\Software\Microsoft\Internet Explorer\Search,CustomizeSearch =
R1 - HKCU\Software\Microsoft\Internet Connection Wizard,ShellNext = http://go.microsoft.com/fwlink/?LinkId=74005
R0 - HKCU\Software\Microsoft\Internet Explorer\Toolbar,LinksFolderName = Collegamenti
O2 - BHO: Java(tm) Plug-In SSV Helper - {761497BB-D6F0-462C-B6EB-D4DAF1D92D43} - C:\Programmi\Java\jre7\bin\ssv.dll
O2 - BHO: Java(tm) Plug-In 2 SSV Helper - {DBC80044-A445-435b-BC74-9C25C1C588A9} - C:\Programmi\Java\jre7\bin\jp2ssv.dll
O4 - HKLM\..\Run: [IgfxTray] C:\WINDOWS\system32\igfxtray.exe
O4 - HKLM\..\Run: [HotKeysCmds] C:\WINDOWS\system32\hkcmd.exe
O4 - HKLM\..\Run: [egui] "C:\Programmi\ESET\ESET NOD32 Antivirus\egui.exe" /hide /waitservice
O4 - HKLM\..\Run: [Adobe ARM] "C:\Programmi\File comuni\Adobe\ARM\1.0\AdobeARM.exe"
O4 - HKLM\..\Run: [SunJavaUpdateSched] "C:\Programmi\File comuni\Java\Java Update\jusched.exe"
O4 - HKCU\..\Run: [ctfmon.exe] C:\WINDOWS\system32\ctfmon.exe
O4 - HKUS\S-1-5-19\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-19\..\RunOnce: [nltide_3] rundll32 advpack.dll,LaunchINFSectionEx nLite.inf,C,,4,N (User 'SERVIZIO LOCALE')
O4 - HKUS\S-1-5-20\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-20\..\RunOnce: [nltide_3] rundll32 advpack.dll,LaunchINFSectionEx nLite.inf,C,,4,N (User 'SERVIZIO DI RETE')
O4 - HKUS\S-1-5-18\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'SYSTEM')
O4 - HKUS\S-1-5-18\..\RunOnce: [nltide_3] rundll32 advpack.dll,LaunchINFSectionEx nLite.inf,C,,4,N (User 'SYSTEM')
O4 - HKUS\.DEFAULT\..\Run: [CTFMON.EXE] C:\WINDOWS\system32\CTFMON.EXE (User 'Default user')
O4 - HKUS\.DEFAULT\..\RunOnce: [nltide_3] rundll32 advpack.dll,LaunchINFSectionEx nLite.inf,C,,4,N (User 'Default user')
O8 - Extra context menu item: E&sporta in Microsoft Excel - res://C:\PROGRA~1\MICROS~1\Office12\EXCEL.EXE/3000
O9 - Extra button: Research - {92780B25-18CC-41C8-B9BE-3C9C571A8263} - C:\PROGRA~1\MICROS~1\Office12\REFIEBAR.DLL
O9 - Extra button: (no name) - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O9 - Extra 'Tools' menuitem: @xpsp3res.dll,-20001 - {e2e2dd38-d088-4134-82b7-f2ba38496583} - C:\WINDOWS\Network Diagnostic\xpnetdiag.exe
O17 - HKLM\System\CCS\Services\Tcpip\..\{482F7447-838C-4E2F-B465-193CD7DCA5CE}: NameServer = 10.204.57.104 10.205.41.16
O17 - HKLM\System\CS1\Services\Tcpip\..\{482F7447-838C-4E2F-B465-193CD7DCA5CE}: NameServer = 10.204.57.104 10.205.41.16
O22 - SharedTaskScheduler: Precaricatore Browseui - {438755C2-A8BA-11D1-B96B-00A0C90312E1} - C:\WINDOWS\system32\browseui.dll
O22 - SharedTaskScheduler: Daemon di cache delle categorie di componenti - {8C7461EF-2B13-11d2-BE35-3078302C2030} - C:\WINDOWS\system32\browseui.dll
O23 - Service: BrSplService (Brother XP spl Service) - brother Industries Ltd - C:\WINDOWS\system32\brsvc01a.exe
O23 - Service: ESET HTTP Server (EhttpSrv) - ESET - C:\Programmi\ESET\ESET NOD32 Antivirus\EHttpSrv.exe
O23 - Service: ESET Service (ekrn) - ESET - C:\Programmi\ESET\ESET NOD32 Antivirus\ekrn.exe
O23 - Service: Servizio Google Update (gupdate) (gupdate) - Google Inc. - C:\Programmi\Google\Update\GoogleUpdate.exe
O23 - Service: Servizio Google Update (gupdatem) (gupdatem) - Google Inc. - C:\Programmi\Google\Update\GoogleUpdate.exe
O23 - Service: Java Quick Starter (JavaQuickStarterService) - Oracle Corporation - C:\Programmi\Java\jre7\bin\jqs.exe
O23 - Service: Mozilla Maintenance Service (MozillaMaintenance) - Mozilla Foundation - C:\Programmi\Mozilla Maintenance Service\maintenanceservice.exe
O23 - Service: Nero BackItUp Scheduler 4.0 - Nero AG - C:\Programmi\File comuni\Nero\Nero BackItUp 4\NBService.exe
O23 - Service: Pml Driver HPZ12 - HP - C:\WINDOWS\system32\HPZipm12.exe
O23 - Service: Wpm Service (Wpm) - Cherished Technololgy LIMITED - C:\Documents and Settings\All Users\Dati applicazioni\WPM\wprotectmanager.exe

--
End of file - 6336 bytes

Dal log non si vedono voci pericolose.
Il problema è che hai ancora il Service Pack 2, dovresti installare il S.P. 3 altrimenti il S.O. non è aggiornabile, è vero che ad aprile 2014 XP non sarà più aggiornato e quindi non protetto quindi o si cambia Sistema Operativo o si va incontro a pericoli.
C'è un programa che mi pare sospetto questo: WPM\wprotectmanager.exe lo conosci ?
Fai sapere. Ciao

Beh...queste non sono proprio uno stinco di santo....

Ciao.