I just replaced the hard drive in my Notebook with a SSD, and added some more memory, then did a fresh install of Windows. Have been able to install everything from system software to productivity software to games, but every time I try to run the installer, it gets most of the way through, then crashes the computer with a blue screen of death, citing an APC Index Mismatch. As I mentioned, I have had no other BSODs except when running the BD installer. Any idea of possible causes? I really want to stay with BitDefender ... it does a quite good job, and is less intense on system resources than any other AV I've tried to use.