Ciao Milvana
Il bimbo stà bene, grazie.
Ci sono delle possibilità concrete che Avast ti abbia rilevato un falso positivo.
Se il pc và bene, è inutile martellarlo.
Non c'è cosa peggiore che cercare un virus che non c'è.
Leggi qui:
http://forum.aiutamici.com/Default.aspx?g=posts&t=56104
Ciao!

Ok....scansione eseguita con avira free come da te suggerito.....spero di aver scelto la scansione completa....ecco il risultato:

Avira AntiVir Personal
Report file date: mercoledì 17 dicembre 2008 22:02

Scanning for 1099136 virus strains and unwanted programs.

Licensed to: Avira AntiVir PersonalEdition Classic
Serial number: 0000149996-ADJIE-0001
Platform: Windows XP
Windows version: (Service Pack 2) [5.1.2600]
Boot mode: Normally booted
Username: SYSTEM
Computer name: YOUR-W2PIMS3OHW

Version information:
BUILD.DAT : 8.2.0.337 16934 Bytes 18/11/2008 13:05:00
AVSCAN.EXE : 8.1.4.10 315649 Bytes 18/11/2008 08:21:28
AVSCAN.DLL : 8.1.4.0 40705 Bytes 26/05/2008 07:56:42
LUKE.DLL : 8.1.4.5 164097 Bytes 12/06/2008 12:44:20
LUKERES.DLL : 8.1.4.0 12033 Bytes 26/05/2008 07:58:54
ANTIVIR0.VDF : 7.1.0.0 15603712 Bytes 27/10/2008 11:30:38
ANTIVIR1.VDF : 7.1.0.197 1170432 Bytes 07/12/2008 20:59:46
ANTIVIR2.VDF : 7.1.0.230 156160 Bytes 14/12/2008 20:59:50
ANTIVIR3.VDF : 7.1.0.249 184320 Bytes 17/12/2008 20:59:54
Engineversion : 8.2.0.45
AEVDF.DLL : 8.1.0.6 102772 Bytes 14/10/2008 10:05:58
AESCRIPT.DLL : 8.1.1.19 336252 Bytes 17/12/2008 21:00:24
AESCN.DLL : 8.1.1.5 123251 Bytes 07/11/2008 15:06:42
AERDL.DLL : 8.1.1.3 438645 Bytes 04/11/2008 13:58:40
AEPACK.DLL : 8.1.3.4 393591 Bytes 11/11/2008 09:41:40
AEOFFICE.DLL : 8.1.0.33 196987 Bytes 17/12/2008 21:00:20
AEHEUR.DLL : 8.1.0.75 1524087 Bytes 17/12/2008 21:00:18
AEHELP.DLL : 8.1.2.0 119159 Bytes 17/12/2008 21:00:04
AEGEN.DLL : 8.1.1.8 323956 Bytes 17/12/2008 21:00:02
AEEMU.DLL : 8.1.0.9 393588 Bytes 14/10/2008 10:05:58
AECORE.DLL : 8.1.5.2 172405 Bytes 17/12/2008 20:59:58
AEBB.DLL : 8.1.0.3 53618 Bytes 14/10/2008 10:05:58
AVWINLL.DLL : 1.0.0.12 15105 Bytes 09/07/2008 08:40:06
AVPREF.DLL : 8.0.2.0 38657 Bytes 16/05/2008 09:28:02
AVREP.DLL : 8.0.0.2 98344 Bytes 31/07/2008 12:02:16
AVREG.DLL : 8.0.0.1 33537 Bytes 09/05/2008 11:26:42
AVARKT.DLL : 1.0.0.23 307457 Bytes 12/02/2008 08:29:24
AVEVTLOG.DLL : 8.0.0.16 119041 Bytes 12/06/2008 12:27:50
SQLITE3.DLL : 3.3.17.1 339968 Bytes 22/01/2008 17:28:04
SMTPLIB.DLL : 1.2.0.23 28929 Bytes 12/06/2008 12:49:42
NETNT.DLL : 8.0.0.1 7937 Bytes 25/01/2008 12:05:12
RCIMAGE.DLL : 8.0.0.51 2371841 Bytes 12/06/2008 13:48:08
RCTEXT.DLL : 8.0.52.0 86273 Bytes 27/06/2008 13:34:38

Configuration settings for the scan:
Jobname..........................: Complete system scan
Configuration file...............: c:\programmi\avira\antivir personaledition classic\sysscan.avp
Logging..........................: low
Primary action...................: interactive
Secondary action.................: ignore
Scan master boot sector..........: on
Scan boot sector.................: on
Boot sectors.....................: C:,
Process scan.....................: on
Scan registry....................: on
Search for rootkits..............: off
Scan all files...................: Intelligent file selection
Scan archives....................: on
Recursion depth..................: 20
Smart extensions.................: on
Macro heuristic..................: on
File heuristic...................: medium

Start of the scan: mercoledì 17 dicembre 2008 22:02

The scan of running processes will be started
Scan process 'avscan.exe' - '1' Module(s) have been scanned
Scan process 'avcenter.exe' - '1' Module(s) have been scanned
Scan process 'avgnt.exe' - '1' Module(s) have been scanned
Scan process 'wuauclt.exe' - '1' Module(s) have been scanned
Scan process 'wuauclt.exe' - '1' Module(s) have been scanned
Scan process 'ApntEx.exe' - '1' Module(s) have been scanned
Scan process 'MSMSGS.EXE' - '1' Module(s) have been scanned
Scan process 'EDICT.EXE' - '1' Module(s) have been scanned
Scan process 'CTFMON.EXE' - '1' Module(s) have been scanned
Scan process 'jusched.exe' - '1' Module(s) have been scanned
Scan process 'WDBtnMgr.exe' - '1' Module(s) have been scanned
Scan process 'TouchED.exe' - '1' Module(s) have been scanned
Scan process 'Apoint.exe' - '1' Module(s) have been scanned
Scan process 'TFNF5.exe' - '1' Module(s) have been scanned
Scan process 'TPWRTRAY.EXE' - '1' Module(s) have been scanned
Scan process '00THotkey.exe' - '1' Module(s) have been scanned
Scan process 'LTSMMSG.exe' - '1' Module(s) have been scanned
Scan process 'PmProxy.exe' - '1' Module(s) have been scanned
Scan process 'hkcmd.exe' - '1' Module(s) have been scanned
Scan process 'igfxtray.exe' - '1' Module(s) have been scanned
Scan process 'EXPLORER.EXE' - '1' Module(s) have been scanned
Scan process 'WMIAPSRV.EXE' - '1' Module(s) have been scanned
Scan process 'ALG.EXE' - '1' Module(s) have been scanned
Scan process 'SMAgent.exe' - '1' Module(s) have been scanned
Scan process 'MDM.EXE' - '1' Module(s) have been scanned
Scan process 'JQS.EXE' - '1' Module(s) have been scanned
Scan process 'GoogleUpdaterService.exe' - '1' Module(s) have been scanned
Scan process 'avguard.exe' - '1' Module(s) have been scanned
Scan process 'sched.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
40 processes with 40 modules were scanned

Starting master boot sector scan:
Master boot sector HD0
[INFO] No virus was found!

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

Starting to scan the registry.
The registry was scanned ( '58' files ).


Starting the file scan:

Begin scan in 'C:\'
C:\pagefile.sys
[WARNING] The file could not be opened!


End of the scan: mercoledì 17 dicembre 2008 22:22
Used time: 20:01 Minute(s)

The scan has been done completely.

5114 Scanning directories
239310 Files were scanned
0 viruses and/or unwanted programs were found
0 Files were classified as suspicious:
0 files were deleted
0 files were repaired
0 files were moved to quarantine
0 files were renamed
1 Files cannot be scanned
239309 Files not concerned
6759 Archives were scanned
1 Warnings
0 Notes

Ciao Shapiro, a questo punto direi che la tua tesi e quella di r16 siano valide pertanto lascio installato avira....però mi togli una curiosità alla voce:
1 Files cannot be scanned
1 Warnings
Pensi che sia tutto ok.......
Grazie ancora per la tua più che ammirevole pazienza e disponibilità.....buona serata.....
Ciao....ciao....