I was waiting to see if anyone answered your post that had personal experience with the software that you mentioned. I've not used it, but I doubt that having the info that it provides is going to help you chase down the issue. Programs like these typically provide screenshots based on a time interval that you select. It is easy to miss screens.
"I want to be able to keep a log file of absolutely everything that is done on the PC every day.
Install process monitor
and you might see 1000s of things happening each second. Too much for one person to research "absolutely everything" that goes on.
Maybe you should make a post in this sub-forum... System Security - Windows 7 Forums
...and see if those experts can point you down the correct path for troubleshooting your issue.