I was attempting to clean a badly infected system recently and to my surprise MBAM would not install. I was in SAFE mode (normal mode was unusable) and when I ran the installer it did nothing. The task manager showed the installer loaded in memory, but inactive. I wonder if MBAM was being specifically targeted by this malware? This was perhaps the worst infection I've seen - internet connectivity was possible in SAFE mode, but DNS was poisoned. There was no host file and I checked the router and TCP/IP DNS settings for tampering, but couldn't find anything. I'm guessing there was cloaked root-kit, but unfortunately I couldn't take the time to figure it out. The system will just be erased and reinstalled next week.