Ok, genau das war mein Problem.

aswMBR version 0.9.9.1649 Copyright(c) 2011 AVAST Software
Run date: 2012-02-28 20:51:55
-----------------------------
20:51:55.115    OS Version: Windows 6.1.7601 Service Pack 1
20:51:55.115    Number of processors: 2 586 0x1706
20:51:55.115    ComputerName: THOMAS-SONY  UserName: Thomas
20:52:19.139    Initialize success
20:52:25.831    AVAST engine defs: 12022801
20:52:29.217    Disk 0 (boot) \Device\Harddisk0\DR0 -> \Device\Ide\IAAStorageDevice-1
20:52:29.232    Disk 0 Vendor: TOSHIBA_ LB01 Size: 190782MB BusType: 3
20:52:29.232    Disk 1  \Device\Harddisk1\DR1 -> \Device\00000086
20:52:29.248    Disk 1 Vendor: RICOH 01 Size: 190782MB BusType: 0
20:52:29.248    Disk 2  \Device\Harddisk2\DR2 -> \Device\00000087
20:52:29.248    Disk 2 Vendor: RICOH 02 Size: 190782MB BusType: 0
20:52:29.264    Disk 0 MBR read successfully
20:52:29.279    Disk 0 MBR scan
20:52:29.279    Disk 0 Windows 7 default MBR code
20:52:29.295    Disk 0 Partition 1 00     27 Hidden NTFS WinRE NTFS         6984 MB offset 2048
20:52:29.326    Disk 0 Partition 2 80 (A) 07    HPFS/NTFS NTFS       183796 MB offset 14305280
20:52:29.326    Disk 0 scanning sectors +390719920
20:52:29.357    Disk 0 malicious Win32:MBRoot code @ sector 390719923 !
20:52:29.404    Disk 0 scanning C:\Windows\system32\drivers
20:52:50.604    Service scanning
20:53:47.638    Modules scanning
20:54:36.622    Disk 0 trace - called modules:
20:54:36.653    ntkrnlpa.exe CLASSPNP.SYS disk.sys shpf.sys ACPI.sys halmacpi.dll iaStor.sys 
20:54:36.669    1 nt!IofCallDriver -> \Device\Harddisk0\DR0[0x870b6030]
20:54:36.685    3 CLASSPNP.SYS[8b99f59e] -> nt!IofCallDriver -> [0x870b41c8]
20:54:36.700    5 shpf.sys[8bbeed03] -> nt!IofCallDriver -> [0x86649840]
20:54:36.700    7 ACPI.sys[8b2323d4] -> nt!IofCallDriver -> \Device\Ide\IAAStorageDevice-1[0x86681028]
20:54:36.716    Scan finished successfully
20:55:21.113    Disk 0 MBR has been saved successfully to "C:\Users\Thomas\Desktop\MBR.dat"
20:55:21.113    The log file has been saved successfully to "C:\Users\Thomas\Desktop\aswMBR.txt"