1. Hire a private investigator.
2. Key loggers will get detected by Antivirus softwares, sometimes creating an exception doesn't help that much and you risk getting caught (Ironic). This is the best option there is and please note its illegal for you to do this if it's not your system.
3. Live...
I had no idea that my phone was keeping such a log, it's just not right if I don't consent to it. No matter if the log never is shared with apple, it should be my decision if I want the phone to keep this log or not.
How much space do you have free on drive C or the drive you have windows installed on? Try freeing disk space as service pack 1 requires that you have more than 8GB free on the drive containing windows.
Similar thing happened with my dell xps 1645, the screen would go black with notifications popping up and displaying fine. Reinstalling dell quickset fixed the problem for me. I am pretty sure it has something to do with power settings, try changing power to performance or balanced and see if it...