Avast Warning: Virus in System memory (But Avast Scan provides no results)

[Aswin_kini]

Hi Friends,
I have a problem with Avast! Yesterday, I ran a virus scan in Thorough mode using Avast! It displayed the message "12/14/2008, 4:48:41 PM
Memory scanning started...
No virus body found in memory.
Memory scanning finished (20.1s).
----------
Files scanning started...
C:\WINDOWS\system32\CatRoot2\tmp.edb... file could not be scanned!
C:\WINDOWS\system32\CatRoot2\edb.log... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Temp\etilqs_nvhnadMZ2zdQz5MJk6wC... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbeam... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbeao... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbdam... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbdao... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbu2d.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbc2e.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbvmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\dbvm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\fiih.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\fii.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\rpmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\rpm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\hpt2i.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-white-domainmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-white-domainm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-black-urlmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-black-urlm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-malware-domainmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-malware-domainm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-black-enchashmh.ht1... file could not be scanned!
C:\Documents and Settings\Administrator\Local Settings\Application Data\Google\Google Desktop Search\safeweb\goog-black-enchashm.cf1... file could not be scanned!
C:\Documents and Settings\Administrator\Application Data\Mozilla\Firefox\Profiles\0y88y8fr.default\places.sqlite-journal... file could not be scanned!
No virus body found.
Files scanning finished  (46016 files, 0 infected, 210.7s).
Drives scanned: C: D: E: F: G: H:"

There were 25 files detected as suspected as malware. I am unable to delete them as they are all .dll files such as spoolsv.exe\..\mdigraph.dll and LMIprinter.dll. When i try to delete one of these files, Avast is displaying the message, "Avast has detected a virus in your system memory, it is dangerous to work on your system. Restart to scan using Avast", when i do restart the system and scan using Avast, it displays 0 infected files. I used SPybot to check for Malware, Spyware and other stuff, even SPYBOT says there are no infected files.

Is there a virus in my system or is this just a false alert from AVast Anti-virus, please help.

Note: My system is functioning normally. I have checked the task manager, the CPU usage is normal.

[FreewheelinFrank]

The files detected as "could not be scanned" are just locked/password protected- nothing to worry about.

You shouldn't try to delete them.

The "Avast has detected a virus in your system memory, it is dangerous to work on your system. Restart to scan using Avast" message when you do try to delete them is very strange, as the scan itself didn't find any virus, either in memory or on the disk.

[DavidR]

See http://forum.avast.com/index.php?topic=35347.msg297170#msg297170 this topic for more information on why files can't be scanned.