I wouldn’t use this for general security as if you make any change it could stuff your system. I have no idea of your experience level, so take this as general advice for others who may well be following this topic or reading it later. This tool should be used under guidance of an experienced malware removal specialist to avoid the pitfalls mentioned before.
The “unknown MBR” is notunusual and may not mean there is an MBR rootkit as many manufacturers (HP, DELL, etc.) may well have a custom MBR to cater for their specific recovery process or system setup.
EDIT: you can attach the aswMBR log and I will try to get a specialist to take a look at it.