quien me ataca?

mi antivirus detecta con frecueia los siguientes ataques:

24/02/2008 21:06:45 HTTP filter file http://rel.statadd.com/d/hmrgas5.exe
Win32/Zapchast.ES trojan connection terminated - quarantined
PRINCIPALPC\MARVI Threat was detected upon access to web by the application:
C:\WINDOWS\system32\svchost.exe.
24/02/2008 20:52:34 Real-time file system protection file
C:\DOCUME~1\MARVI\CONFIG~1\Temp\13exhmrgas5.exe Win32/Zapchast.ES trojan
cleaned by deleting - quarantined NT AUTHORITY\SYSTEM Event occurred during
an attempt to access the file by the application:
C:\WINDOWS\system32\svchost.exe.
24/02/2008 20:51:46 HTTP filter file http://rel.statadd.com/d/hmrgas5.exe
Win32/Zapchast.ES trojan connection terminated - quarantined
PRINCIPALPC\MARVI Threat was detected upon access to web by the application:
C:\WINDOWS\system32\svchost.exe.
24/02/2008 19:50:31 HTTP filter file http://rel.statadd.com/d/hmrgas5.exe
Win32/Zapchast.ES trojan connection terminated - quarantined
PRINCIPALPC\MARVI Threat was detected upon access to web by the application:
C:\WINDOWS\system32\svchost.exe.


que debo hacer...???

saludos y gracias a todos