Hi,
was sagt denn das Ereignislog?
Und bezüglich des Virenscanners empfehle ich dir die Artikel mal durchzulesen:
Antivirus, backup, and disk optimization programs that are compatible with the File Replication Service
Virus scanning recommendations for computers that are running Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows 2000, Windows XP, or Windows Vista
LG