Virus que j'arrive pas a supprimer

Bonjour,
Sur l'ordi de ma petite soeur , antivir me trouve plein de virus mais le probléme c'est qu'il revienne toujours si quelqu'un peu m'aider merci

voi le raport du dernier scanner d'antivir

' - '1' Module(s) have been scanned
Scan process 'LVComSX.exe' - '1' Module(s) have been scanned
Scan process 'avgnt.exe' - '1' Module(s) have been scanned
Scan process 'QuickCam10.exe' - '1' Module(s) have been scanned
Scan process 'Communications_Helper.exe' - '1' Module(s) have been scanned
Scan process 'jusched.exe' - '1' Module(s) have been scanned
Scan process 'rundll32.exe' - '1' Module(s) have been scanned
Scan process 'alg.exe' - '1' Module(s) have been scanned
Scan process 'explorer.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'StarWindService.exe' - '1' Module(s) have been scanned
Scan process 'nvsvc32.exe' - '1' Module(s) have been scanned
Scan process 'sched.exe' - '1' Module(s) have been scanned
Scan process 'LVPrcSrv.exe' - '1' Module(s) have been scanned
Scan process 'spoolsv.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'svchost.exe' - '1' Module(s) have been scanned
Scan process 'lsass.exe' - '1' Module(s) have been scanned
Scan process 'services.exe' - '1' Module(s) have been scanned
Scan process 'winlogon.exe' - '1' Module(s) have been scanned
Scan process 'csrss.exe' - '1' Module(s) have been scanned
Scan process 'smss.exe' - '1' Module(s) have been scanned
Process 'printer.exe' has been terminated
C:\WINDOWS\system32\printer.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
[INFO] The file was moved to '47428fec.qua'!

37 processes with 36 modules were scanned

Start scanning boot sectors:
Boot sector 'C:\'
[NOTE] No virus was found!

Starting to scan the registry.
C:\WINDOWS\system32\winavxx.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
[INFO] The file was moved to '47478fe7.qua'!
C:\WINDOWS\system32\winavxx.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
C:\WINDOWS\system32\winavxx.exe
[WARNING] The file could not be opened!
C:\Documents and Settings\All Users\Menu Démarrer\Programmes\Démarrage\autorun.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
[INFO] The file was moved to '474d8ff3.qua'!
C:\Documents and Settings\All Users\Menu Démarrer\Programmes\Démarrage\autorun.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
C:\Documents and Settings\justine\Menu Démarrer\Programmes\Démarrage\system.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
[INFO] The file was moved to '474c8ff8.qua'!
C:\Documents and Settings\justine\Menu Démarrer\Programmes\Démarrage\system.exe
[DETECTION] Is the Trojan horse TR/Agent.16896

The registry was scanned ( '24' files ).


Starting the file scan:

Begin scan in 'C:\'
C:\pagefile.sys
[WARNING] The file could not be opened!
C:\Documents and Settings\parents\Menu Démarrer\Programmes\Démarrage\system.exe
[DETECTION] Is the Trojan horse TR/Agent.16896
[INFO] The file was moved to '474c9c61.qua'!
C:\Program Files\Navilog1\navilog1.bat
[DETECTION] Contains suspicious code HEUR/Exploit.HTML
[INFO] The file was moved to '474f9ed7.qua'!
C:\WINDOWS\system32\hadjajr.VIR
[DETECTION] Is the Trojan horse TR/Qhost.MY.1
[INFO] The file was moved to '473da2a4.qua'!
C:\WINDOWS\system32\drivers\sptd.sys
[WARNING] The file could not be opened!


End of the scan: samedi 1 septembre 2007 19:35
Used time: 1:23:29 min

The scan has been done completely.

4946 Scanning directories
215469 Files were scanned
8 viruses and/or unwanted programs were found
1 classified as suspicious:
0 files were deleted
0 files were repaired
7 files were moved to quarantine
0 files were renamed
3 Files cannot be scanned
215460 Files not concerned
2236 Archives were scanned
3 Warnings
0 Notes
0 Hidden objects were found