I have the same problem as the first two users. Malwarebytes Pro, XP, Avira, Zonealarm. Updated Malwarebytes and computer basically froze, mouse moves but nothing works, no clicks, windows key, ctrl-alt-delete, nada. Hard reboot, froze somewhere during startup but after icons loaded and some activity. Hard reboot, safe mode, mbam-clean. Reboot, we're good. Disable avira and secunia, install mbam, we're good. Register for pro and turn on real time protection, frozen. Hard reboot, cheated and just killed mbam exes through task. Read your above post above about disabling ZA as well, so did so. mbam-clean, reboot, we're good. Disable avira, disable ZA, install mbam, we're good. Register mbam, we're good. Re-enable ZA, frozen. So I'm guessing conflict is with ZA, specifically I'm still running 9.2 instead of 2012.